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# Science Reviewer: 450+ Questions for NAT and High School Entrance Exam

## Compilation of Science review questions for NAT and high school entrance examinations

Whether you’re a student doing self-review, a teacher preparing review materials for your class, or a parent looking for resources to help your child, this comprehensive compilation of Science questions will surely be helpful to you as you get ready for the National Achievement Test (NAT) for Grade 6 and/or the Science High, University of the Philippines (UP), and other high school entrance examinations.

Further below, you can download a printable (PDF) copy of the questions with their answers. The questions are divided into 4 sets (Set A to D) and the answer key is found on the last page of each PDF.

See also: Math Reviewer: 150+ Questions for NAT and High School Entrance Exam

Good luck!

## Science Reviewer

1. A mixture is a combination of two or more substances. When it appears uniform all throughout, it is called a _____.

a. homogeneous mixture
b. heterogeneous mixture
c. homozygous mixture
d. heterozygous mixture

2. Which of the following does NOT describe a heterogeneous mixture?

a. The composition of the mixture is the same all throughout.
b. The composition of the mixture is visible.
c. The composition of the mixture can be easily identified.
d. None – all are correct

3. A mixture that is formed when one substance dissolves into another is called a _____.

a. solute
b. solvent
c. solution
d. compound

4. Which of the following statements is correct?

a. A solution is a heterogeneous mixture.
b. A solvent is the substance that is being dissolved.
c. A solute is the substance that does the dissolving.
d. Water is called the “universal solvent” because it is able to dissolve more substances than any other liquid.

5. Which of these factors affect solubility?

a. the size of the solute
b. the amount of the solvent
c. the temperature of the solvent
d. all of the above

6. True or False – A solution always consists of a liquid solvent and a solid solute.

a. true
b. false

7. Steel is an example of a _____.

a. colloid
b. compound
c. solution
d. suspension

8. Clean air is an example of a _____.

a. colloid
b. compound
c. solution
d. suspension

9. Which of these mixtures is homogeneous?

a. colloid
b. solution
c. suspension
d. all of the above

10. Which of these mixtures is heterogeneous?

a. colloid
b. solution
c. suspension
d. a & c

11. Three beakers contain a solution, a colloid, and a suspension, but you don’t know which is which. You notice that in one of the beakers, particles have settled at the bottom. This must be the _____.

a. colloid
b. solution
c. suspension

12. Three beakers contain a solution, a colloid, and a suspension, but you don’t know which is which. In one of the beakers, particles have NOT settled at the bottom over time, and when you shine a light through it, the light scatters, like car headlights in a fog. This must be the _____.

a. colloid
b. solution
c. suspension

13. The _____ is used to determine whether a mixture is a true solution or a colloid.

a. Tydings-McDuffie law
b. Tyndall effect
c. Tycho Brahe test
d. Tympanic membrane

14. Aerosol, foam, emulsion, and sol are types of _____.

a. colloids
b. solutions
c. suspensions
d. all of the above

15. This is a type of mixture where liquid or solid particles are dispersed in a gas. Examples include fog, mist, and smoke.

a. emulsion
b. aerosol
c. gel
d. foam

16. When you go to the beach, you notice that rough waves or swimmers can disturb the sand in the sea but it usually settles back down to the bottom. This is an example of a _____.

a. colloid
b. compound
c. solution
d. suspension

17. Most materials are mixtures. They may be mixtures of elements or mixtures of compounds. Which of the following is a mixture?

a. water
b. sea water
c. carbon dioxide
d. salt

18. The bubbling in soft drinks or sodas is due to _____.

a. the sugar in the liquid
b. the alcohol in the liquid
c. the air dissolved in the liquid
d. the carbon dioxide dissolved in the liquid

19. At construction sites, stones and all sorts of debris can get mixed into the sand. To get the stones out, construction workers often use which separation technique?

a. sieving
b. evaporation
c. decantation
d. distillation

20. You can use a magnet to separate _____.

a. sand from gravel
b. sand from aluminum powder
c. sand from iron filings
d. sand from sugar

21. You need to separate two liquids that have different densities. Which separation technique can you use?

a. filtration
b. decantation
c. using a magnet
d. sieving

22. Alum is used in the process of water purification called _____.

a. boiling
b. distillation
c. coagulation
d. aeration

23. When you dry your clothes by spinning them in the washing machine, you are using a separation technique called centrifugation. But when you dry the clothes by hanging them outside, on a clothesline, under the heat of the sun, you are using which separation technique?

a. still centrifugation
b. filtration
c. evaporation
d. distillation

24. Water is composed of _____.

a. carbon and oxygen
b. nitrogen and oxygen
c. hydrogen and oxygen
d. carbon and nitrogen

25. Which of these statements is incorrect?

a. All living things need energy to carry out life processes.
b. All living things are composed of one or more cells.
c. All living things reproduce.
d. All living things maintain a stable external environment.

26. Which of these statements is correct?

a. Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species
b. Kingdom > Domain > Phylum > Class > Order > Family > Genus > Species
c. Domain > Kingdom > Phylum > Class > Order > Family > Species > Genus
d. Kingdom > Domain > Phylum > Class > Order > Family > Species > Genus

27. Archaea were previously thought to be bacteria but scientists have since discovered that their DNA have distinct differences. In which of these ways are bacteria and archaea different?

a. The absence of a nucleus
b. The number of cells composing each organism
c. The ability to reproduce asexually
d. The presence of peptidoglycan in their cell walls

28. Extremophiles live in habitats that are intolerably hostile or even lethal to most other life-forms. These habitats include hydrothermal vents, frozen sea water, extremely acidic or basic environments, and even toxic waste. While extremophiles can come from either of the three domains of life – archaea, bacteria, and eukarya – the main group to thrive in extreme environments are the:

a. archaeans
b. bacteria
c. eukaryotes

29. Tardigrades can survive temperatures ranging from −272°C to 151°C, pressures of 6,000 atm, extreme dehydration, and exposure to X-rays and gamma rays. They belong to which domain?

a. archaea
b. bacteria
c. eukarya

30. All of these organisms are eukaryotes except _____.

a. bacteria
b. fungi
c. plants
d. protists

31. Which of these statements is incorrect?

a. A molecule is a combination of two or more atoms.
b. A molecule that consists of more than one element is called a compound.
c. The oxygen in the air we breathe – O2 – is a compound.
d. Carbon dioxide – CO2 – is a compound.

32. Salt (NaCl), water (H2O), and carbon dioxide (CO2) are examples of _____.

a. atoms
b. elements
c. compounds
d. solids

33. Molecules built around the element carbon are called _____.

a. organic compounds
b. inorganic compounds
c. volatile substances
d. minerals

34. Living things are made up of the following classes of organic compounds except _____.

a. carbohydrates
b. lipids
c. proteins
d. hydrocarbons

35. The enzymes and antibodies in our bodies are examples of _____.

a. carbohydrates
b. lipids
c. proteins
d. nucleic acids

36. Plants store sugar in the form of starch, while animals store sugar in the form of glycogen. Both starch and glycogen are examples of _____.

a. carbohydrates
b. lipids
c. proteins
d. nucleic acids

37. The cholesterol that we use to make many things in the body and the double layer that makes up the outer membranes of our cells are both examples of _____.

a. carbohydrates
b. lipids
c. proteins
d. nucleic acids

38. DNA stores our genetic information while RNA helps make proteins. Both DNA and RNA are examples of _____.

a. carbohydrates
b. lipids
c. proteins
d. nucleic acids

39. The building blocks of proteins are called _____.

a. amino acids
b. monosaccharides
c. fatty acids
d. nucleotides

40. Proteins that speed up chemical reactions are called _____.

a. enzymes
b. hormones
c. collagens
d. albumin

41. A _____ is the smallest structural and functional unit of an organism.

a. cell
b. tissue
c. organ
d. organ system

42. What does the cell theory NOT say?

a. All organisms are composed of cells.
b. Cells are alive and the basic living units of organization in all organisms.
c. All cells come from other cells.
d. Cells can neither be created nor destroyed.

43. Which is correct?

a. Cell > organ > organelle > organ system > organism
b. Cell > tissue > organ > organ system > organism
c. Cell > organ > organ system > tissue > organism
d. Cell > organelle > organ > organ system > organism

44. Which statement is incorrect?

a. There are two basic types of cells: prokaryotic cells and eukaryotic cells.
b. Prokaryotic cells do not have DNA.
c. Prokaryotic cells do not have a nucleus.
d. Eukaryotic cells have a nucleus where their DNA is stored.

45. Which statement is incorrect?

a. All prokaryotes are unicellular.
b. Bacteria and archaea are prokaryotes.
c. All eukaryotes are multicellular.
d. All multicellular organisms are eukaryotes.

46. The following are found in both prokaryotes and eukaryotes EXCEPT _____.

a. cytoplasm
b. ribosomes
c. DNA
d. mitochondria

47. The following are present in eukaryotic cells and absent in prokaryotic cells EXCEPT:

a. nucleus
b. mitochondria
c. ribosomes
d. Golgi apparatus

48. Which organelle contains the genetic material of the cell?

a. nucleus
b. mitochondria
c. ribosomes
d. rough endoplasmic reticulum

49. Which organelle is known as the powerhouse of the cell because it is where ATP – the form of energy used in cells – is produced?

a. nucleus
b. mitochondria
c. ribosomes
d. rough endoplasmic reticulum

50. Which organelle is where proteins are produced?

a. nucleus
b. mitochondria
c. ribosomes
d. rough endoplasmic reticulum

51. Which organelle is covered with ribosomes and is involved in the processing of protein?

a. nucleus
b. mitochondria
c. ribosomes
d. rough endoplasmic reticulum

52. Which organelle is where lipids are produced?

a. smooth endoplasmic reticulum
b. Golgi apparatus
c. lysosome
d. nucleolus

53. Which organelle receives proteins from the rough ER, packages them, and sends them off to the appropriate place in the cell or cell membrane?

a. smooth endoplasmic reticulum
b. Golgi apparatus
c. lysosome
d. nucleolus

54. Which organelle is in charge of dealing with the cell’s waste, generally by using its digestive enzymes to break them down into parts that can be recycled?

a. smooth endoplasmic reticulum
b. Golgi apparatus
c. lysosome
d. nucleolus

55. Which organelle is in charge of producing and assembling ribosomes?

a. smooth endoplasmic reticulum
b. Golgi apparatus
c. lysosome
d. nucleolus

56. _____ are small membrane-bound sacs that transport materials around the cell.

a. vesicles
b. vacuoles
c. centrioles
d. chloroplasts

57. _____ are the cells’ storage centers.

a. vesicles
b. vacuoles
c. centrioles
d. chloroplasts

58. In the process of manufacturing food, plants _____.

a. create energy
b. destroy energy
c. store the energy from the sun
d. do not require energy from the sun

59. Photosynthesis is the process by which plant cells convert _____ into chemical energy in the form of glucose.

a. hydrocarbons
b. the sun’s energy
c. water and oxygen
d. nitrogen, phosphorus, and potassium

60. Which organelles in the plant cell are in charge of photosynthesis?

a. vesicles
b. vacuoles
c. centrioles
d. chloroplasts

61. These are the ways in which plant cells differ from animal cells EXCEPT _____.

a. Only plant cells have cell walls.
b. Only plant cells have chloroplasts.
c. Only plant cells have vacuoles.
d. No exception

62. Plant cells have organelles called plastids. Which statement about the different types of plastids is incorrect?

a. Chloroplasts are in charge of photosynthesis.
b. Leucoplasts store leucocytes.
c. Chromoplasts give some flowers and fruits their yellow, orange, or red color.
d. None – all are correct

63. The number of calories in food indicates _____.

a. the vitamin content in the food
b. the weight of the food per unit volume
c. the amount that can be digested from the food
d. the amount of energy that can be obtained from the food

64. Nutrients are chemicals needed by our body that are found in food. There are five types of nutrients: carbohydrates, proteins, _____, vitamins, and minerals.

a. collagen
b. rice
c. lipids
d. sugars

65. Among the five types of nutrients, our main source of energy is _____.

a. carbohydrates
b. proteins
c. vitamins
d. minerals

66. True or False – Our body can get energy from carbohydrates, lipids, and proteins.

a. true
b. false

67. Sugar and starches are _____.

a. fats
b. proteins
c. minerals
d. carbohydrates

68. Sugars are small, simple carbohydrates that are found in foods such as rice, fruits, and milk. The simplest sugar is called _____.

a. glucose
b. fructose
c. lactose
d. galactose

69. Which simple carbohydrate is converted by cells into ATP through the process of cellular respiration?

a. rice
b. starch
c. glucose
d. wheat

70. The sugar found in fruits is called _____.

a. glucose
b. fructose
c. lactose
d. galactose

71. Complex carbohydrates are larger than simple carbohydrates like glucose. Our bodies break them down more slowly compared to simple carbohydrates. They can give us energy more steadily and for a longer period of time. This is why it is better if the carbohydrates in our food are complex carbohydrates. The following are complex carbohydrates except _____.

a. starch
b. fiber
c. galactose
d. none – all are correct

72. Which of these is a large, complex carbohydrate that is partly indigestible?

a. starch
b. fiber
c. table sugar
d. calcium

73. Proteins are made up of smaller molecules called_____.

a. fibrins
b. amino acids
c. proteases
d. carnitines

74. Our body can make its own proteins, but to do so, it needs amino acids, which we can get from eating _____.

a. carbohydrates
b. proteins
c. vitamins
d. minerals

75. The following are rich in protein, except _____.

a. lean meat
b. banana
c. peanut butter
d. sea food

76. Which nutrient stores energy, protects nerves, cushions internal organs, and makes up the membranes that surround cells?

a. carbohydrates
b. lipids
c. vitamins
d. minerals

77. There are two main types of fats. Which type of fat is more often found in meat, full-fat dairy products, eggs, and tropical oils like coconut and palm oil? This type of fat increases cholesterol levels in the blood, which can lead to heart disease.

a. saturated fat
b. unsaturated fat
c. trans fat
d. none of these

78. There are two main types of fats. Which type of fat is more often found in plant-based oils (such as olive, soybean, corn, canola, and sunflower oil) and fish? When eaten in moderation, this type of fat can have a positive effect on our health.

a. saturated fat
b. unsaturated fat
c. trans fat
d. none of these

79. Most unsaturated fats are “healthy” or “good” fats. An exception to this is _____. This type of fat increases our risk of heart disease and provides no benefits to our health. Unfortunately, this is the type of fat that is commonly found in foods we normally like, such as french fries, microwave popcorn, doughnuts, and baked goods sold in stores, such as cakes and cookies.

a. saturated fat
b. unsaturated fat
c. trans fat
d. none of these

80. True or False – Like other nutrients, vitamins and minerals give us energy.

a. true
b. false

81. Which vitamin is incorrectly paired with its role in the body?

a. Vitamin A – for good vision
b. Vitamin B1 – for healthy nerves
c. Vitamin C – for blood clotting
d. Vitamin D – for healthy bones and teeth

82. Minerals are chemical elements that are needed for body processes. Which mineral is incorrectly paired with its role in the body?

a. calcium – for strong bones and teeth
b. iron – for making hemoglobin, which carries oxygen in red blood cells
c. potassium – for muscles to work properly
d. none – all are correct

83. Digestion begins in the _____.

a. mouth
b. esophagus
c. stomach
d. small intestine

84. The rhythmic, wave-like movement of the digestive tract is called _____.

a. emesis
b. harmonic propulsion
c. peristalsis
d. traction

85. Final digestion and food absorption take place in the _____.

a. stomach
b. small intestine
c. large intestine
d. rectum

86. The _____ is the system that is in charge of breaking down the food we eat into a form that can be absorbed by our cells.

a. respiratory system
b. circulatory system
c. digestive system
d. excretory system

87. The process of breaking down food into absorbable nutrients is called _____.

a. respiration
b. digestion
c. absorption
d. nutrition

88. Our digestive system is basically one long tube plus a few accessory organs that release “juices” into it. This tube is called the _____.

a. small intestine
b. large intestine
c. gastrointestinal tract
d. none of these

89. What type of digestion is the process of physically breaking down the food we eat into smaller and smaller pieces? It is also known as physical digestion.

a. chemical digestion
b. mechanical digestion
c. cellular digestion
d. indigestion

90. What type of digestion is the process of breaking down large food molecules into small nutrient molecules – changing the actual chemical structure of the food particles and turning it into a form that can be absorbed into the blood?

a. chemical digestion
b. structural digestion
c. mechanical digestion
d. cellular digestion

91. An enzyme is a protein that speeds up chemical reactions in the body. Digestive enzymes play a huge role in which type of digestion?

a. mechanical digestion
b. chemical digestion
c. both
d. neither

92. Which of these statements about digestive enzymes is incorrect?

a. Protease breaks down proteins.
b. Lipase breaks down fats.
c. Carbohydratase breaks down carbohydrates.
d. None – all are correct

93. The substance secreted by the liver that helps in the digestion of fats is _____.

a. ptyalin
b. bile
c. pancreatic juice
d. intestinal juice

94. Bile helps in the digestion of lipids. Which organ produces bile?

a. pancreas
b. liver
d. kidney

95. What type of digestion happens in the mouth?

a. mechanical digestion
b. chemical digestion
c. both
d. neither

96. What type of digestion happens in the esophagus?

a. mechanical digestion
b. chemical digestion
c. both
d. neither

97. What type of digestion happens in the stomach?

a. mechanical digestion
b. chemical digestion
c. both
d. neither

98. What type of digestion happens in the small intestine?

a. mechanical digestion
b. chemical digestion
c. both
d. neither

99. Chewing is part of _____.

a. chemical digestion
b. enzymatic digestion
c. mechanical digestion
d. cellular digestion

100. The organs of the digestive system are lined with muscles that contract, or tighten, in waves in order to push food through the system. This series of muscle contractions is called _____.

a. borborygmi
b. intubation
c. peristalsis
d. cramps

101. Digestion begins in the _____.

a. small intestine
b. esophagus
c. mouth
d. stomach

102. What do you call the tube that connects your mouth to your stomach?

a. biliary tract
b. rectum
c. colon
d. esophagus

103. Most of the work of chemical digestion takes place in the _____.

a. mouth
b. small intestine
c. stomach
d. large intestine

104. Which organ(s) make juices that help to dissolve and digest your food?

a. liver
b. pancreas
c. both
d. neither

105. Which organ(s) stores bile and releases it when needed?

c. pancreas
d. salivary glands

106. Which is longer?

a. the large intestine
b. the small intestine
c. the two are equally long

107. The later parts of the small intestine are covered by millions of tiny projections called _____, which have blood vessels through which nutrients are absorbed.

a. cilia
b. villi
c. glands
d. nodes

108. What absorbs spare water and forms what isn’t absorbed into lumps of waste?

a. anus
b. large intestine
c. pancreas

109. An estimated 100 trillion bacteria live in our gut! We help the bacteria – by giving them a safe environment to live – and they help us. Which of these do the “good bacteria” in our gut do for us?

a. Produce vitamin B12 and vitamin K
b. Control the growth of harmful bacteria
c. Produce enzymes that digest carbohydrates in plant cell walls, making us able to digest plant foods like spinach
d. All of these

110. Solid waste leaves your body through the _____.

b. lungs
c. rectum
d. skin

111. To get food into your body, your mouth needs to open. Which organ system helps with this?

a. muscular system
b. nervous system
c. skeletal system
d. all of these

112. Which organ system helps the most in moving the food that you eat along the digestive tract? (Aside from the nervous system, of course, which coordinates everything!)

a. endocrine system
b. integumentary system
c. muscular system
d. renal system

113. Which organ system distributes the nutrients obtained by the digestive system to your whole body?

a. circulatory system
b. distributive system
c. immune system
d. integumentary system

114. Hormones affect many processes in the digestive system, like the release of acid in the stomach, the release of bile from the gallbladder, and how fast the intestines move. Which organ system is most involved in this?

a. endocrine system
b. integumentary system
c. respiratory system
d. skeletal system

115. When your stomach is full, it tells your brain that you have already had enough food, and you stop eating. When your stomach and intestines are empty, they signal the brain that you need food, and so you start to feel hungry. This shows how your digestive system works together with which other system?

a. lymphatic system
b. nervous system
c. respiratory system
d. urinary system

116. _____ is the process of removing waste and excess water from the body.

a. Excretion
b. Respiration
c. Condensation
d. Filtration

117. Which is an incorrect pairing between the body waste and the organ responsible for excreting it?

a. feces – large intestine
b. carbon dioxide – lungs
c. water and salts – skin and kidneys
d. none – all are correct

118. Our bodies lose water through the following processes, except _____.

a. sweating
b. breathing
c. urination
d. none – all are correct

119. Which organ is part of the excretory system?

a. lungs
b. skin
c. kidneys
d. all of these

120. Which statement about the organs of the excretory system is incorrect?

a. The lungs, which are also a part of the respiratory system, are responsible for excreting carbon dioxide in the air we breathe out.
b. The skin, which is also a part of the muscular system, excretes water, salts, and other wastes in the form of sweat.
c. The large intestine, which is also a part of the digestive system, excretes solid waste in the form of feces.
d. The kidneys, which are part of the urinary system, are responsible for excreting salts, urea, and excess water in the form of urine.

121. The job of the _____ is to protect the body.

a. immune system
b. endocrine system
c. skeletal system
d. muscular system

122. A _____ is an organism that can cause disease.

a. villus
b. pathogen
c. protease
d. teratogen

123. The _____ forms a physical barrier between the body and the outside world. For this reason, it is the body’s first and most important line of defense against infection.

a. white blood cells
b. muscles
c. skin
d. lymph nodes

124. Our mouth and nose, as well as organs that are exposed to things coming from the outside world such as our stomach and lungs, are not lined with skin. Instead, they are lined with _____ that have special structures that fight against “invaders.”

a. fur
b. scales
c. white blood cells
d. mucous membranes

125. Mucous membranes are covered by a moist, sticky substance called _____. Because it is sticky, most pathogens and foreign particles get stuck in it and do not get the opportunity to do harm to the body.

a. mucus
b. sap
c. cytoplasm
d. lymph

126. Hair-like projections called _____ are also found in mucous membranes. They move in waves, sweeping mucus with its trapped pathogens and particles toward body openings.

a. brushes
b. cilia
c. flagella
d. phagocytes

127. Lysozymes are chemicals that can kill pathogens. They are found in all of the following, except _____.

a. sweat
b. tears
c. saliva
d. none – all are correct

128. True or False – Hydrochloric acid, which is also known as muriatic acid and is used in many household cleaning solutions, is also used by the body to protect itself against pathogens.

a. true
b. false

129. True or False – Bacteria can help our bodies fight against disease-causing organisms.

a. true
b. false

130. When pathogens are able to get through the body’s first lines of defense – for example, when there is a break in the skin, like a cut or a scrape – the body sets off an inflammatory response. The blood vessels near the affected area dilate (become wider). This allows more blood to reach the injured part. It also allows more immune system cells (such as white blood cells) to get to the area, where they then go out of the blood vessels and go towards the site of injury. The following are signs of an ongoing inflammatory response (or inflammation) except _____.

a. redness
b. swelling
c. warmth
d. none – all are correct

131. There are certain kinds of white blood cells that go to areas of inflammation and “eat” pathogens, foreign particles, and dead cells. In this way they are able to help the body eliminate these unwanted “invaders.” The cells that do this are called _____.

a. lysozymes
b. erythrocytes
c. myocytes
d. phagocytes

132. True or False – A fever can help the body fight infection.

a. true
b. false

133. The immune system has two subsystems: (1) the innate or non-specific immune system, and (2) the adaptive or specific immune system. Which of these provides a general defense against harmful germs and substances?

a. innate immune system
c. both
d. neither

134. The immune system has two subsystems: (1) the innate or non-specific immune system, and (2) the adaptive or specific immune system. Which of these makes antibodies and uses them to fight certain germs that the body has previously come into contact with?

a. innate immune system
c. both
d. neither

135. An _____ is a molecule that the immune system identifies as foreign and responds to by forming antibodies.

a. antibiotic
b. antigen
c. allele
d. amylase

136. Which of these statements about our body’s specific immune response is incorrect?

a. B-cells make antigens, proteins that bind to antibodies on the outside of pathogens. This binding signals phagocytes to engulf and destroy the pathogen.
b. Killer T cells destroy body cells that are infected with pathogens. They also destroy damaged or cancerous body cells.
c. Helper T cells release chemicals that “switch on” both B cells and killer T cells so they can recognize and fight specific pathogens.
d. None – all are correct

137. _____ is the process of deliberately exposing a person to a pathogen so that they can develop immunity. Only part of the pathogen is injected, or a weak or dead pathogen is used. This imitates an infection and triggers an immune response where the body prepares “memory” cells for use at a later time, so that the body can recognize and fight off the antigen if it is ever encountered again.

a. Pathogenization
b. Indoctrination
c. Impersonation
d. Vaccination

138. What is the smallest living thing that can cause disease in humans?

a. virus
b. bacteria
c. protozoans
d. pollen

139. The following are parts of the appendicular skeleton except _____.

a. carpals
b. ribs
c. tarsals
d. ulna

140. Which of the following pairings is incorrect?

a. femur – long bone
b. pinkie finger – short bone
c. skull – flat bone
d. spinal column – irregular bone

141. The skeletal system includes the following, except _____.

a. bones
b. cartilage
c. ligaments
d. none – all are correct

142. Bones, cartilage, and ligaments make up the _____ system.

a. muscular
b. integumentary
c. renal
d. none of these

143. How many bones does the adult human skeleton have?

a. 164
b. 206
c. 256
d. 408

144. Our bones have many roles. The following are a few of their most important functions, except _____.

a. support against gravity
b. storage of certain minerals
c. making blood cells
d. none – all of these are functions of bones

145. Which of these bones belong to the appendicular skeleton?

a. breastbone
b. kneecap
c. skull
d. tailbone

146. The bone at the tip of your pinkie (smallest finger) is a _____.

a. long bone
b. short bone
c. flat bone
d. irregular bone

147. The _____ is the tough, fibrous membrane that covers and protects the outer surface of bones.

a. periosteum
b. endosteum
c. epiphysis
d. bone marrow

148. The bone tissue that makes up the dense outer layer of bones is _____.

a. bone marrow
b. compact bone
c. trabecular bone
d. ligaments

149. The light, porous bone tissue that is typically found at the ends of long bones is the _____, also called cancellous bone. It is usually surrounded by a shell of compact bone, for greater strength and rigidity, but it provides balance to compact bone (which is dense and heavy) by making bones lighter so that muscles can move them more easily.

a. bone marrow
b. compact bone
c. spongy bone
d. ligaments

150. Some long bones have bone marrow, which is important because the bone marrow is where _____.

a. insulin is produced
b. blood cells are produced
c. calcium is produced
d. calcitonin is produced

151. Which statement is true?

a. Bones stop growing in length during early adulthood.
b. Bones can continue to increase in thickness throughout life.
c. Both
d. Neither

152. The smallest bone in the body is found in your _____.

a. hand
b. feet
c. nose
d. ear

153. The _____ is the smallest bone in your body.

a. coccyx
b. hyoid
c. stapes
d. patella

154. The longest bone in your body is the _____.

a. tibia
b. fibula
c. femur
d. humerus

155. A break in a bone is called a _____.

a. sprain
b. strain
c. fracture
d. dislocation

156. A _____ is a short band of tough connective tissue that connects bones together to form a joint.

a. cartilage
b. ligament
c. tendon
d. bone marrow

157. Injuries to ligaments are called _____.

a. sprains
b. strains
c. fractures
d. dislocations

158. The point at which two or more bones meet is called a _____.

a. fracture
b. overlap
c. cartilage
d. joint

159. Joints are classified based on either (1) the kind of tissue that they have, or (2) how much movement they allow. The following are the types of joints based on tissue type, except _____.

a. fibrous
b. cartilaginous
c. ligamentous
d. synovial

160. Joints are classified based on either (1) the kind of tissue they have, or (2) how much movement they allow. The following are the types of joints based on the amount of movement allowed within the joint, except _____.

a. fixed joints, also known as synarthroses or immovable joints
b. partly movable joints, also known as amphiarthroses or slightly moveable joints
c. movable joints, also known as diarthroses or freely moveable joints
d. none – all are correct

161. The joints between the plate-like bones of our skull are _____.

a. fixed joints
b. partly movable joints
c. movable joints
d. synovial joints

162. The joints between the vertebrae of our backbone are _____.

a. fixed joints
b. partly movable joints
c. movable joints
d. synovial joints

163. Our shoulder joints are _____.

a. fixed joints
b. partly movable joints
c. movable joints
d. fibrous joints

164. Our knee joints are _____.

a. fixed joints
b. partly movable joints
c. movable joints
d. fibrous joints

165. Ball-and-socket, hinge, pivot, and gliding joints are all types of _____.

a. fixed joints
b. partly movable joints
c. movable joints
d. fibrous joints

166. The type of movable joint that allows motion in two directions, forward and backward, is the _____.

a. ball-and-socket joint
b. hinge joint
c. pivot joint
d. gliding joint

167. The type of movable joint that only allows rotating movement is the _____. An example of this is the joint between your radius and your ulna, the two bones in your forearm. Movement at this joint allows you to flip your palm over without having to move your elbow joint.

a. ball-and-socket joint
b. hinge joint
c. pivot joint
d. gliding joint

168. The shoulder joint is a _____.

a. ball-and-socket joint
b. hinge joint
c. pivot joint
d. gliding joint

169. The hip joint is a _____.

a. ball-and-socket joint
b. hinge joint
c. pivot joint
d. gliding joint

170. The knee is a _____.

a. ball-and-socket joint
b. hinge joint
c. pivot joint
d. gliding joint

171. The elbow is a _____.

a. ball-and-socket joint
b. hinge joint
c. pivot joint
d. gliding joint

172. The joints in your wrists and your ankles are examples of _____.

a. ball-and-socket joints
b. hinge joints
c. pivot joints
d. gliding joints

173. Muscles work closely with our bones and connective tissues in order to make our body move. Nearly all the movement in our body is the result of muscle contraction. When muscles contract, they _____.

a. lengthen
b. shorten
c. relax
d. narrow

174. There are three different types of muscles in our body. The type of muscle that is under our conscious control is the _____. They are the muscles responsible for voluntary movement.

a. skeletal muscle
b. smooth muscle
c. cardiac muscle
d. none of these

175. There are three different types of muscles in our body. The type of muscle found within the walls of organs and blood vessels is the _____. They work automatically without us being aware of them and so they are also known as involuntary muscles.

a. skeletal muscle
b. smooth muscle
c. cardiac muscle
d. none of these

176. The special muscle that makes up our heart is the _____. It is strong enough to pump out blood to our entire body. Although this muscle is similar in appearance to voluntary muscle because it is also striated, it is actually involuntary – you can never consciously tell your heart to stop working.

a. skeletal muscle
b. smooth muscle
c. cardiac muscle
d. none of these

177. The type of muscle generally responsible for the contraction of hollow organs such as the uterus and the urinary bladder is _____.

a. skeletal muscle
b. smooth muscle
c. cardiac muscle
d. none of these

178. Muscles are attached to bones by a tough cord of connective tissue called a _____.

a. ligament
b. tendon
c. orbit
d. patella

179. When muscles contract, they pull on the tendons, which in turn pull on the _____. In this way, the pull of contracting muscles allows you to move.

a. bone
b. nerve
c. skin
d. joint fluid

180. Muscles can only _____; they cannot _____. That is why, to move bones in opposite directions, they need to work in pairs.

a. grow; atrophy
b. increase; decrease
c. go up; go down
d. pull; push

a. uniceps
b. triceps
d. gastrocnemius

a. pulls
b. shortens
c. relaxes
d. assists in contraction

183. The muscle that contracts to cause a joint to bend is called the _____.

a. extensor
b. flexor
c. agonist
d. antagonist

184. The muscle that contracts to cause the joint to straighten is called the _____.

a. extensor
b. flexor
c. agonist
d. antagonist

185. These types of muscles are striated, except _____.

a. skeletal muscle
b. smooth muscle
c. cardiac muscle
d. none – all are striated

186. These types of muscles are involuntary, except _____.

a. skeletal muscle
b. smooth muscle
c. cardiac muscle
d. none – all are involuntary

187. A sudden, involuntary, and often painful contraction of one or more of your muscles is called a _____. It is also called a “muscle spasm.”

a. cramp
b. sprain
c. strain
d. contusion

188. When a muscle is stretched too much, it can tear. This is called a muscle _____. It is also known as a pulled muscle.

a. cramp
b. sprain
c. strain
d. contusion

189. This is what happens when something hits a part of your body and damages the muscles and connective tissue underneath but doesn’t break the skin. It is commonly known as a bruise.

a. fracture
b. splinter
c. contusion
d. strain

190. When you have a strain or sprain, you are often advised to do R.I.C.E.: rest, ice, compression, and _____.

a. exaggeration
b. excitation
c. elevation
d. empathy

191. The outermost layer of the skin is the _____.

a. dermis
b. epidermis
d. hypodermis

192. Which of the following is NOT a function of the integumentary system?

a. defense against pathogens
b. elimination of waste products
c. regulation of body temperature
d. none – all are correct

193. The following are part of the integumentary system except _____:

a. bones
b. hair
c. nails
d. skin

194. Which statement about the skin’s important functions is incorrect?

a. The skin acts as a barrier that keeps out organisms that might be harmful.
b. The skin produces sweat when it is hot. The sweat uses some of the heat in the body to evaporate – in this way, it helps cool the body down. Sweat also brings out waste such as ammonia and urea.
c. The skin helps us gather information about our environment, using special nerve endings that sense heat, cold, pressure, and pain.
d. None – all are correct

195. _____ is the pigment in our skin that, like a natural sunblock, helps protect us from harmful ultraviolet light. It is brown and is responsible for the color of our skin and hair.

a. Niacin
b. Melanin
c. Tannin
d. Caffeine

196. The outermost layer of the skin is called the _____.

a. dermis
b. epidermis
c. hypodermis
d. subcutis

197. The cells that produce melanin – the pigment that gives our skin and hair their color – are found in which layer of the skin?

a. dermis
b. epidermis
c. hypodermis
d. subcutis

198. True or False – The epidermis does not have any blood vessels.

a. true
b. false

199. True or False – There are no nerve endings in nails.

a. true
b. false

200. The layer of skin directly under the epidermis is called the _____.

a. stratum corneum
b. stratum granulosum
c. hypodermis
d. dermis

201. Which of these structures are found in the dermis?

a. hair follicles
b. oil glands
c. sweat glands
d. all of these

202. The structure from where a hair grows is called the _____.

a. strand
b. hair follicle
c. hair gland
d. keratin

203. What does the dermis do?

a. Keeps skin strong and flexible thanks to its collagen and elastin
b. Grows hair
c. Produces sweat and oil
d. All of these

204. The nerve endings that sense touch, heat, pressure, and pain are located in the _____.

a. epidermis
b. dermis
c. both
d. neither

205. The hair helps with all of the following except _____.

a. sensation
b. keeping the body warm
c. protection from dust, sunlight, etc.
d. none – all are correct

206. The part of the respiratory system that is also known as the windpipe is the _____.

a. bronchi
b. larynx
c. pharynx
d. trachea

207. The _____ are grape-like air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place.

a. alveoli
b. bronchi
c. bronchioles
d. diaphragm

208. The liquid part of the blood is called the _____.

a. blood corpuscles
b. hematocrit
c. hemoglobin
d. plasma

209. Leukocytes are also known as _____.

a. red blood cells
b. white blood cells
c. platelets
d. plasma

210. The blood vessels that carry deoxygenated blood back to the heart are the _____.

a. arteries
b. veins
c. capillaries
d. none of the above

211. How many chambers does the human heart have?

a. 2
b. 3
c. 4
d. 6

212. The system that controls and coordinates the activities of the body is the _____.

a. circulatory system
b. endocrine system
c. excretory system
d. nervous system

213. The following are parts of the brain except _____.

a. brain cord
b. brain stem
c. cerebellum
d. cerebrum

214. Which part of the nerve cell receives signals and passes them on to the main part of the cell?

a. axons
b. neurons
c. dendrites
d. cell bodies

215. Which statement is correct?

a. Sensory neurons carry messages from the brain to the effector organs.
b. Motor neurons carry messages from receptor organs to the brain.
c. Interneurons connect sensory and motor neurons in the peripheral nervous system.
d. None – all are incorrect

216. The division of the autonomic nervous system that produces opposing effects to the sympathetic nervous system is the _____.

a. parasympathetic nervous system
b. peripheral nervous system
c. somatic nervous system
d. unsympathetic nervous system

217. Which system sends electrical messages throughout the body and controls all other body systems?

a. nervous system
b. endocrine system
c. digestive system
d. circulatory system

218. The following are the main organs of the nervous system except:

a. brain
b. spinal cord
c. mental prominence
d. no exceptions – all three are the main organs of the nervous system

219. These are the main parts of a neuron, except:

a. cell body
b. dendrites
c. axon
d. myofibrils

220. The _____ receive nerve impulses from other cells.

a. dendrites
b. axons
c. myelin sheath
d. nodes of Ranvier

221. The _____ passes nerve impulses on to other cells.

a. dendrite
b. axon
c. myelin sheath
d. node of Ranvier

222. The _____ is the fatty layer that insulates the axon and allows electrical signals to travel much more quickly.

a. dendrite
b. synaptic cleft
c. myelin sheath
d. neuroplasm

223. The place where the axon of one neuron meets the dendrites of another neuron is called the _____.

a. synapse
b. node of Ranvier
c. neural junction
d. myelin sheath

224. Which of these statements is incorrect?

a. Sensory neurons carry nerve impulses from sense organs and internal organs to the central nervous system.
b. Motor neurons carry nerve impulses from the central nervous system to organs, glands, and muscles.
c. Synapses can also be found between neurons and other types of cells, such as muscle cells.
d. None – all are correct

225. When a nerve impulse reaches the end of an axon, the axon releases chemicals that travel across the synapse between the axon and the dendrite of the next neuron. When these chemicals bind to the membrane of the dendrite, this “passes the message” and prompts a nerve impulse to then travel through the receiving neuron. These chemicals are called _____.

a. neurotransmitters
b. hormones
c. enzymes
d. none of the above

226. The three main parts of the brain are the _____.

a. cerebrum, cerebellum, brainstem
b. cerebrum, cerebellum, midbrain
c. cerebrum, cerebellum, spinal cord
d. cerebrum, cerebellum, medulla

227. The _____ is the largest and top-most part of our brain. It controls functions that we are aware of, such as voluntary movements, language, and problem-solving.

a. cerebrum
b. cerebellum
c. brainstem
d. pons

228. The part of our brain that controls balance, coordination, and body position is the _____.

a. cerebrum
b. cerebellum
c. brainstem
d. pons

229. The _____ is responsible for many vital functions of life, such as breathing, consciousness, blood pressure, heart rate, and sleep.

a. cerebrum
b. cerebellum
c. brainstem
d. spinal cord

230. Which of these statements is incorrect?

a. The cerebrum is divided into two hemispheres: right and left.
b. Each hemisphere has four sections, or lobes: frontal, parturial, temporal, and occipital.
c. The two cerebral hemispheres are connected by a thick bundle of axons called the corpus callosum.
d. The right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body.

231. The lobe of the brain most involved in reasoning, learning, voluntary motion, and “executive functions” like self-control and attention is the _____.

a. frontal lobe
b. parietal lobe
c. temporal lobe
d. occipital lobe

232. The lobe of the brain most involved in processing information from your eyes is the _____.

a. frontal lobe
b. parietal lobe
c. temporal lobe
d. occipital lobe

233. The main function of the _____ is to carry nerve signals from your brain to your body and vice versa.

a. spinal cord
b. interneurons
c. hippocampus
d. basal ganglia

234. Our sense organs don’t recognize, by themselves, what they are sensing. Rather, they send messages about sights, smells, and other stimuli to our brain, and then our brain interprets the messages and tells us what it is we are detecting through our senses. The nerve cells responsible for carrying these messages from our sense organs to our brain are the _____.

a. sensory neurons
b. motor neurons
c. interneurons
d. bioneurons

235. The part of the peripheral nervous system that is responsible for movements within our control is the _____.

a. autonomic nervous system
b. sensory nervous system
c. somatic nervous system
d. voluntary nervous system

236. The part of the peripheral nervous system that carries nerve impulses to our internal organs and controls activities that are not under our control, such as digestion and sweating, is the _____.

a. sensory nervous system
b. autonomic nervous system
c. somatic nervous system
d. central nervous system

237. The part of the autonomic nervous system that controls our internal organs and glands during emergencies and is responsible for our “fight or flight” response is the _____.

a. sensory nervous system
b. sympathetic nervous system
c. parasympathetic nervous system
d. stress nervous system

238. The part of the autonomic nervous system that relaxes our body after periods of stress, and is in charge during “rest and digest” conditions, when there is no emergency, is the _____.

a. sensory nervous system
b. sympathetic nervous system
c. parasympathetic nervous system
d. baseline nervous system

239. Which is not a part of the urinary system?

a. kidneys
b. ureters
d. urethra

240. Which organ/s filter salts, nitrogen-containing molecules, and excess water from the blood?

a. kidneys
b. ureters
d. urethra

241. The _____ are the tubes through which urine passes from the kidneys to the urinary bladder.

a. glomeruli
b. ureters
c. urethrae
d. Fallopian tubes

242. The _____ is a hollow, muscular organ with stretchy walls. It collects and stores urine until it is ready to be excreted.

a. urethra
b. ureter
c. uterus

243. Where does the ureter lead to?

a. kidney
c. urethra
d. uterus

244. Blood flows into the kidney through the _____.

a. urinary artery
b. ulnar artery
c. renal artery
d. peroneal artery

245. What is a nitrogen-containing molecule that is made when foods that contain protein – such as meat and certain vegetables – are broken down in the body?

a. urea
b. NaCl
c. nitrous oxide
d. sodium nitrate

246. A dehydrated person is more likely to have _____.

a. light-colored urine
b. dark-colored urine
c. red-colored urine
d. huge amounts of urine

247. Our kidneys help us maintain homeostasis. Which statement about what our kidneys do is incorrect?

a. They regulate the amount of water in our body.
b. They pause filtration when we sleep to conserve energy.
c. They maintain the balance of salt ions in our body fluids.
d. They excrete harmful nitrogen-containing molecules, such as urea, ammonia, and uric acid.

248. Each of our kidneys is made up of about a million nephrons. A nephron is called the functional unit of the kidneys because it carries out the kidneys’ work. Which statement about the nephron and its parts is not true?

a. Each nephron is made up of two glomeruli and a tubule.
b. The glomerulus filters the blood. Its thin walls allow smaller molecules, wastes, and water to pass into the tubule.
c. As the filtered fluid moves along the tubule, the tubule returns the substances that our body still needs back to our blood and removes the waste.
d. Most of the water and other substances that are filtered through the glomeruli are returned to the blood by the tubules.

249. The urinary system interacts with the body’s other organ systems in the production and excretion of urine. The circulatory system transports the blood to and from the kidneys. Urination involves the contraction of muscles. You can tell when your urinary bladder is getting full because the nerves in the bladder send alerts to your brain. The endocrine system also interacts with the urinary system through the antidiuretic hormone (ADH). Which of these statements about ADH is incorrect?

a. ADH is a hormone made by the hypothalamus and its release is controlled by the pituitary gland. Both the hypothalamus and the pituitary gland are part of the endocrine system.
b. If you have too little water in your body, ADH is released, and it instructs your kidneys to reabsorb more water (so that you don’t get even more dehydrated).
c. When you have a lot of water in your body, there will be less ADH released, less water will be reabsorbed into the blood, and your urine will look darker.
d. None – all are correct.

250. The following vertebrates are cold-blooded except _____.

a. amphibians
b. birds
c. fish
d. reptiles

251. Crocodiles are _____.

a. amphibians
b. cnidarians
c. flightless birds
d. reptiles

252. Which vertebrate – body covering pairing is incorrect?

a. amphibians – moist, scaly skin
b. fish – scales
c. mammals – hair or fur
d. reptiles – dry, scaly skin

253. Sponges belong to which group of invertebrates?

a. annelids
b. cnidarians
c. echinoderms
d. poriferans

254. Sea stars, sea urchins, and sea cucumbers are _____.

a. arthropods
b. coelenterates
c. echinoderms
d. mollusks

255. Which pairing is incorrect?

a. crabs – arthropods
b. snails – mollusks
c. tapeworms – nematodes
d. none – all are correct

256. The topmost layer of the rainforest is the _____.

a. canopy
b. emergent
c. understory
d. forest floor

257. What process takes place when a sperm cell fuses with an egg cell?

a. reproduction
b. fertilization
c. hibernation
d. interaction

258. What is the process by which an organism produces another individual that is biologically similar to itself?

a. reproduction
b. fertilization
c. hibernation
d. interaction

259. A fertilized egg is called a _____.

a. ovum
b. zygote
c. embryo
d. fetus

260. The following are agents of pollination except _____.

a. bees
b. butterflies
c. dogs
d. dragonflies

261. This occurs when pollen from one flower is deposited on the stigma of the same flower or another flower of the same plant.

a. cross-pollination
b. self-pollination
c. asexual pollination
d. asexual reproduction

262. This occurs when pollen from one flower is deposited on the stigma of a flower on another plant of the same species.

a. cross-pollination
b. self-pollination
c. vegetative pollination
d. vegetative reproduction

263. These specialized plant structures are horizontal stems that grow along the surface of the soil. When they make proper contact with a moist soil surface, roots can grow from their nodes.

a. rhizomes
b. runners
c. suckers
d. tubers

264. These specialized plant structures are horizontal stems that grow underground. Roots and shoots originate from their nodes. When separated, each piece is capable of producing a new plant as it grows up out of the ground.

a. rhizomes
b. runners
c. suckers
d. tubers

265. These specialized plant structures are upright or vertical shoots that arise from the base or roots of the parent plant.

a. rhizomes
b. runners
c. suckers
d. tubers

266. These specialized plant structures are thick, fleshy, storage stems. They have buds called “eyes” that can develop into new individuals under proper conditions.

a. rhizomes
b. runners
c. suckers
d. tubers

267. In this method of propagation, a portion of the stem, root, or leaf is cut and planted to develop into a new plant.

a. cutting
b. grafting
c. layering
d. marcotting

268. In this method of propagation, a stem from one plant is cut and attached to the stump of another plant.

a. cutting
b. grafting
c. layering
d. marcotting

269. In this method of propagation, a stem is bent and covered with soil to induce root formation, then separated from the parent plant.

a. budding
b. grafting
c. layering
d. marcotting

270. In this method of propagation, a ring of bark is removed from a branch. The exposed area is wrapped with soil or another rooting medium and covered with plastic to retain moisture. This induces roots to grow on a stem while it is still attached to the parent plant. It is also known as air layering.

a. budding
b. cutting
c. grafting
d. marcotting

271. Pollinators such as bees drink nectar from flowers and, as they move around, carry pollen from the male part of the flower to the female part of the same or another flower. This is an example of which type of relationship?

a. commensalism
b. competition
c. mutualism
d. parasitism

272. The following are types of coral reef formations except _____.

a. atolls
b. barrier reefs
c. bleaching reefs
d. fringing reefs

273. Mudskippers are most likely found in which habitat?

a. coral reefs
b. mangrove swamps
c. tropical rainforests
d. tundra

274. Which is NOT a reason why mangrove swamps are important?

a. They serve as breeding and nesting grounds for many animal species.
b. They serve as natural barriers, protecting the coastline from flooding and erosion.
c. They are an important source of livelihood for people living in coastal areas.
d. None – all are correct

275. Energy usually enters ecosystems as:

a. stored energy in plants
b. chemical energy in nutrients
c. mechanical energy from the wind
d. sunlight

276. A place where freshwater from a river mixes with saltwater from the sea

a. canopy
b. estuary
c. intertidal zone
d. tundra

277. Area that is covered by water during high tide but is exposed or above the water level during low tide

a. canopy
b. estuary
c. intertidal zone
d. tundra

278. Which statement is true about the nature of matter?

a. The molecules in a solid are smooth and flow easily.
b. Compounds are the simplest particles in nature.
c. Atoms are either liquids or gases only.
d. The molecules in a liquid flow and take the shape of the container.

279. Which of the following is not found in the nucleus of an atom?

a. proton
b. electron
c. neutron
d. none – they’re all located in the nucleus

280. Which of these has a negative charge?

a. proton
b. electron
c. neutron
d. none of the above

281. Which of these has a positive charge?

a. proton
b. electron
c. neutron
d. none of the above

282. Which of these has a neutral charge?

a. proton
b. electron
c. neutron
d. none of the above

283. Which of these statements is false?

a. Protons have an electric charge of +1.
b. Electrons have an electric charge of -1.
c. Atoms have the same number of protons and electrons.
d. Because the nucleus has a greater mass, atoms have an overall positive charge.

284. Which of the following statements is not true about the nucleus of an atom?

a. It is very dense.
b. It has an overall positive charge.
c. It contains practically all the mass of the atom.
d. The positively-charged protons in the nucleus do not repel each other because of the presence of the negatively-charged neutrons.

285. A positively charged particle _____.

a. has more electrons than protons
b. has more protons than electrons
c. has more neutrons than electrons
d. has an equal number of protons and electrons

286. A negatively charged particle _____.

a. has more electrons than protons
b. has more protons than electrons
c. has more neutrons than electrons
d. has an equal number of protons and electrons

287. Which of these statements is true?

a. Friction opposes the motion of objects.
b. Friction can occur even between surfaces that are not in contact with each other.
c. Friction acts in the same direction as the object’s motion.
d. Friction speeds up the movement of objects.

288. What is the direction of friction between a moving object and a surface?

a. toward the direction of the object’s motion
b. in the same direction as the object’s motion
c. opposite to the direction of the object’s motion
d. perpendicular to the direction of the object’s motion

289. Will it be easier for a person to push a table on a carpeted floor than on a waxed floor?

a. Yes, because the carpeted floor is smoother, so the friction is lesser.
b. Yes, because the carpeted floor is smoother, so the friction is greater.
c. No, because the carpeted floor is rougher, so the friction is lesser.
d. No, because the carpeted floor is rougher, so the friction is greater.

290. A person is pushing a grocery cart northwards. In what direction is friction acting on the cart?

a. north
b. south
c. east
d. west

291. Which statement is correct?

a. The smaller the surface area of the objects in contact with each other, the greater the friction and the longer the distance travelled.
b. The smaller the surface area of the objects in contact with each other, the greater the friction and the shorter the distance travelled.
c. The bigger the surface area of the objects in contact with each other, the greater the friction and the longer the distance travelled.
d. The bigger the surface area of the objects in contact with each other, the greater the friction and the shorter the distance travelled.

292. Oil is put on the bearing of wheels to _____.

a. reduce friction
b. give the wheels more force
c. change the direction of the motion
d. increase the speed at which the wheels turn

293. True or False – Friction can be helpful.

a. true
b. false

294. We get our energy from the food we eat, which stored that energy in what form?

a. nuclear energy
b. thermal energy
c. chemical energy
d. mechanical energy

295. The type of energy that is found in objects that are moving or have the potential to move is _____.

a. electrical energy
b. nuclear energy
d. mechanical energy

296. The form of energy that is generated when an object vibrates is _____.

a. vibrant energy
c. sound
d. light

297. The type of energy that is stored in the bonds between the atoms that make up compounds is _____.

a. mechanical energy
b. chemical energy
c. electrical energy
d. nuclear energy

298. True or False – When you are perched on top of a water slide, you have mechanical energy.

a. true
b. false

299. When you light a candle, which energy transformation takes place?

a. light → chemical and heat
b. light → mechanical and heat
c. chemical → light and heat
d. chemical → electrical and heat

300. The energy that is contained in fuel is an example of _____.

b. chemical energy
c. mechanical energy
d. electrical energy

301. What is almost always produced when there is energy transformation?

a. heat
b. light
c. electricity
d. chemical energy

302. The law of _____ of energy states that energy can neither be created nor destroyed. It can be transformed/converted from one form to another but the total amount of energy remains the same.

a. transformation
b. transition
c. conversion
d. conservation

303. You are one of the students assigned to raise the Philippine flag during your school’s flag ceremony. What simple machine are you using to pull it up?

a. inclined plane
b. lever
c. pulley
d. wedge

304. Simple machines are common in our day-to-day lives. When you chop onions for cooking, you are actually using which simple machine?

a. lever
b. pulley
c. screw
d. wedge

305. Chances are, you bring one or more simple machines to school every day. When you open and close the lid of your water bottle, what kind of simple machine are you using?

a. inclined plane
b. screw
c. wedge
d. wheel and axle

306. Most buildings have ramps that people on wheelchairs can navigate more easily than stairs. A wheelchair is an example of a device that has a wheel and axle, while the ramp is an example of which simple machine?

a. inclined plane
b. lever
c. screw
d. wheel and axle

307. The fixed point of a lever is known as the _____.

b. force
c. fulcrum
d. pivot

308. There are three classes of levers, based on the position of their effort, load, and fulcrum. Which of these levers does not belong to the same class as the others?

a. scissors
b. seesaw
c. tongs
d. none – all three belong to the same class of lever

309. When boiling water is poured into a cold milk bottle, the bottle will often break because _____.

a. glass is a good conductor of heat
b. milk bottles are made of extremely thin glass
c. the boiling water dissolves the inner part of the glass
d. the inside of the bottle expands faster than the outside

310. The force that an object exerts on a given unit of area is called _____.

a. weight
b. volume
c. density
d. pressure

311. The density of an object is equal to the ratio of its mass to its volume. An object can float in water if its density is less than 1 g/cm3. What will happen if a 1 cm x 2 cm x 3 cm piece of aluminum with a mass of 16 grams is placed in a swimming pool?

a. It will sink.
b. It will float.
c. It will float but be partially submerged in water.
d. It will dissolve.

312. An object immersed in water displaces a volume of water _____.

a. equal to its own volume
b. less than its own volume
c. greater than its own weight
d. equal to its own weight

313. A long steel suspension bridge sags several centimeters in summer because _____.

a. the heat causes the steel to expand
b. the bridge was not properly constructed
c. the steel becomes softer due to the heat
d. the increased traffic in summer causes increased weight on the bridge

314. You put a piece of metal pipe in front of your eyes, but the pipe is bent and so you can’t see through it. This is because _____.

a. mirrors reflect rays of light
b. lenses bend rays of light
c. metal reflect rays of light
d. light travels in a straight line

315. A material is said to be transparent if _____.

a. it reflects light
b. it emits light
c. light can pass freely through it in a straight line
d. it absorbs light and redistributes the energy as heat

316. Of all the electromagnetic waves _____ have the highest energy while _____ have the lowest.

b. visible light; infrared
c. x-rays; infrared

317. True or False – Electromagnetic waves can transfer energy through matter or across empty space.

a. true
b. false

318. True or False – Electromagnetic waves travel at the speed of light through empty space.

a. true
b. false

319. Which statement is false?

a. Wave frequency is the number of waves that pass a fixed point in a given amount of time.
b. Wavelength is the distance between corresponding points of adjacent waves.
c. The lower the frequency, the lower the wavelength of an electromagnetic wave, and the less likely it is to be harmful.
d. High-frequency waves have a lot of energy and are more likely to be harmful.

320. Which of these electromagnetic waves have the longest wavelengths?

b. microwaves
c. X-rays
d. gamma rays

321. Among these electromagnetic waves, which has the least amount of energy?

a. microwaves
b. light
c. X-rays
d. gamma rays

322. Cell phone signals are carried through the air as which electromagnetic wave?

b. microwaves
c. X-rays
d. gamma rays

323. Radar uses which type of electromagnetic wave?

a. ultraviolet
b. microwaves
c. X-rays
d. gamma rays

324. Which of these electromagnetic waves have the highest frequencies?

b. microwaves
c. X-rays
d. gamma rays

325. Sunlight contains _____.

a. only visible light
b. infrared light and visible light
c. infrared light, visible light, and ultraviolet light
d. the entire electromagnetic spectrum

326. Which of these statements is false?

a. You can’t see infrared light but you can feel it as heat.
b. Night vision goggles can detect infrared light waves and convert them to visible images.
c. We see light of different wavelengths as different colors of light.
d. Ultraviolet light has more energy because it has a higher wavelength, that’s why it can be used to kill bacteria in food and sterilize surgical instruments.

327. Which of these statements is false?

a. X-rays have enough energy to pass through soft tissues such as skin.
b. X-rays cannot pass through bones and teeth.
c. X-rays have the highest energy among all electromagnetic waves.
d. You should limit your exposure to X-rays because they can be harmful.

328. Which of these statements is false?

a. Gamma rays have a frequency of approximately 10 quadrillion waves per second.
b. Like X-rays, gamma rays cannot pass through bones and teeth.
c. Most gamma rays from space are absorbed by the earth’s atmosphere before they can reach the surface.
d. Sources of gamma rays include stars, radioactive atoms, and nuclear explosions.

329. When light cannot pass through and bounces back from the surface of an object, this is called _____.

a. reflection
b. refraction
c. absorption
d. transmission

330. This is when light is neither reflected or transmitted and instead transfers its energy to an object, as in the case of a car becoming very hot when it has been sitting under the sun all day, particularly when it is dark in color.

a. refraction
b. scattering
c. absorption
d. diffusion

331. When light is _____, it changes direction as it passes into a new medium and changes speed.

a. reflected
b. refracted
c. absorbed
d. transmitted

332. Matter that transmits light without scattering it is _____.

a. transparent
b. translucent
c. opaque

333. Matter that transmits light but scatters the light as it passes through is _____.

a. transparent
b. translucent
c. opaque

334. Matter that does not let any light pass through it is _____.

a. transparent
b. translucent
c. opaque

335. Opaque matter may do all of the following except _____.

a. absorb light
b. reflect light
c. a combination of absorption and reflection
d. transmit light without scattering it

336. Your black shirt absorbs all light while your blue jeans absorb some light and reflect the rest. You check your appearance in the mirror. Your black shirt is _____, your blue jeans are _____, and your mirror is _____.

a. transparent; translucent; opaque
b. opaque; translucent; opaque
c. opaque; opaque; transparent
d. opaque; opaque; opaque

337. The beautiful colors of the rainbow _____.

a. are produced when sunlight is refracted by raindrops
b. are produced when sunlight is reflected by raindrops
c. are produced by atmospheric gases
d. are produced when clouds reflect sunlight

338. A person standing waist-deep in a swimming pool appears to have short legs because of _____.

a. reflection
b. refraction
c. absorption
d. diffusion

339. At which time of the day would you have the shortest shadow?

a. morning
b. noon
c. afternoon
d. evening

a. When light rays hit hard objects.
b. When light rays hit opaque objects.
c. When light rays hit translucent objects.
d. When light rays hit the transparent objects.

341. _____ is the bending of light as it passes through different materials.

a. Absorption
b. Infraction
c. Reflection
d. Refraction

342. _____ is the bouncing back of light when it hits an object.

a. Absorption
b. Infraction
c. Reflection
d. Refraction

343. _____ is the transfer of light energy to materials rather than being reflected or transmitted.

a. Absorption
b. Infraction
c. Reflection
d. Refraction

344. Which of the following is TRUE about force?

a. Force can change the shape or size of an object.
b. Force can change only the direction of an object.
c. Force cannot change the speed of a moving object.
d. Force can change the chemical properties of objects.

345. The greater the mass of an object, the greater is the force needed to _____ the object.

a. move
b. push
c. stop
d. all of the above

346. Which of the following cannot be attracted by magnets?

a. cobalt
b. gold
c. iron
d. nickel

347. Which of the following statements is correct?

a. Magnets do not have force.
b. Paper can be attracted by magnets.
c. All metals can be attracted by magnets.
d. The push and pull of magnets is called magnetic force.

348. Which of the following is NOT true about magnetic force?

a. Like poles of two magnets repel each other.
b. The force of attraction is greater at the middle of a magnet.
c. Opposite poles of two magnets attract each other.
d. Magnets attract objects made up of iron, cobalt and nickel.

349. What is the direction of flow of heat transfer?

a. from hot to cold
b. from cold to hot
c. from top to bottom
d. sidewards

350. Heat can travel through solids by _____.

a. conduction
b. convection
d. insulation

351. The transfer of heat energy through direct contact between the heat source and another object is called _____.

a. conduction
b. convection
d. insulation

352. The transfer of heat by the movement of the heated parts of fluids such as liquid or gas is called _____.

a. conduction
b. convection
d. insulation

353. This method of heat transfer is the reason why we have wind movements and local breezes.

a. conduction
b. convection
d. insulation

354. Heat is transmitted across empty space or vacuum through _____.

a. conduction
b. convection
d. insulation

355. This method of heat transfer does not depend on the presence of matter to transfer heat.

a. conduction
b. convection
d. insulation

356. Materials such as metals that allow heat to flow through easily are described as good _____.

a. conductors
b. insulators
d. indicators

357. Materials through which heat passes slowly or not at all are called _____.

a. conductors
b. insulators
d. indicators

358. A material that allows electricity to pass through it is called a _____.

a. conductor
b. electrode
c. insulator

359. A material that does not allow electricity to pass through it is called a _____.

a. conductor
b. electrode
c. insulator

360. A circuit where the connection is not broken, enabling electricity to flow

a. open circuit
b. closed circuit
c. parallel circuit
d. series circuit

361. A circuit where the path is broken, preventing the flow of electric current

a. open circuit
b. closed circuit
c. parallel circuit
d. series circuit

362. A circuit in which components are connected end-to-end, forming a single path for current

a. open circuit
b. closed circuit
c. parallel circuit
d. series circuit

363. A circuit in which components are connected across each other, providing multiple paths for current

a. open circuit
b. closed circuit
c. parallel circuit
d. series circuit

364. A circuit in which, when one bulb burns out, the other bulbs will not function anymore

a. AC circuit
b. DC circuit
c. parallel circuit
d. series circuit

365. This electrical safety device contains a thin metal wire or strip that melts when exposed to excessive current. This melting breaks the circuit, stopping the flow of electricity.

a. circuit breaker
b. defibrillator
c. fuse
d. insulation

366. This electrical safety device trips when it detects excess current from an overload or short circuit, interrupting current flow. It can be reset and so can be used again.

a. circuit breaker
b. defibrillator
c. fuse
d. insulation

367. A device made temporarily magnetic by electricity

a. electromagnet
b. ferrovoltaic device
c. magnetometer
d. solenoid

368. The following are the three types of plate tectonic boundaries, except:

a. divergent
b. convergent
c. emergent
d. transform

369. The _____ is the point of origin of an earthquake underground.

a. breaking point
b. focus
c. epicenter
d. fault

370. The _____ is the point on the surface of the Earth that is directly above an earthquake’s underground point of origin.

a. breaking point
b. focus
c. epicenter
d. fault

371. A _____ is a crack in the Earth’s crust between two big plates.

a. breaking point
b. focus
c. epicenter
d. fault

372. When rock masses move and change in position, the energy stored in them is released and transmitted to the surface in the form of seismic waves. This causes _____.

a. earthquakes
b. volcanic eruptions
c. typhoons
d. storm surges

373. An earthquake that is due to sudden movement of rocks, such as when two tectonic plates collide against each other

a. tectonic earthquake
b. volcanic earthquake
c. endemic earthquake

374. An earthquake that results from the movement of magma within volcanoes

a. tectonic earthquake
b. volcanic earthquake
c. endemic earthquake

375. An earthquake triggered by human activity such as massive explosions and fluid injection or extraction, also known as induced seismicity

a. tectonic earthquake
b. volcanic earthquake
c. endemic earthquake

376. A _____ is a series of giant waves caused by earthquakes or volcanic eruptions under the sea.

a. storm surge
b. tsunami
c. seismic wave
d. barrel

377. Which layers of the Earth make up the lithosphere?

a. mantle and outer core
b. mantle and inner core
c. crust and upper mantle
d. outer core and inner core

378. Which is made up of the liquid part of the mantle and the outer core?

a. outer core group
b. crust
c. lithosphere
d. asthenosphere

379. The seasons in the Philippines are caused by:

a. its location on the equator
b. prevailing winds
c. both
d. neither

380. This is also known as the southwest monsoon and brings warm and moist air into the country.

a. Amihan
b. Habagat
c. Sirocco
d. Delubyo

381. This is also known as the northeast monsoon and brings cool, dry air into the country.

a. Amihan
b. Habagat
c. Sirocco
d. Delubyo

382. Which is also known as the Hanging Amihan?

a. northeast monsoon
b. northwest monsoon
c. southwest monsoon
d. southeast monsoon

383. Which is also known as the Hanging Habagat?

a. northeast monsoon
b. northwest monsoon
c. southwest monsoon
d. southeast monsoon

384. Which brings warm and moist air into the country?

a. hanging Amihan
b. hanging Habagat
c. northwest monsoon
d. southeast monsoon

385. Which brings cool, dry air into the country?

a. hanging Amihan
b. hanging Habagat
c. northwest monsoon
d. southeast monsoon

386. Which brings moist, warm air into the country that makes rains heavier and typhoons stronger?

a. cold fronts
c. northeast monsoon
d. southwest monsoon

387. Which of the following is the effect of the Earth’s tilt and revolution?

a. movement of wind
b. occurrence of tides
c. occurrence of seasons
d. movement of water in seas

388. Which of the following statements is true?

a. The Earth rotates on its axis once every 12 hours.
b. The Earth rotates on its axis once every 24 hours.
c. The Earth rotates on its axis once every 365 hours.
d. The Earth rotates on its axis once every 365 days.

389. Which of these is the pathway of the Earth around the sun?

a. axis
b. orbit
c. ring
d. space

390. Which statement about the Earth is false?

a. The Earth spins on its axis.
b. The Earth revolves around the sun.
c. The sun revolves around the Earth.
d. The Earth travels on its orbit around the sun.

391. How much time would it take for the Earth to complete one revolution?

a. 7 days
b. 30 days
c. 24 hours
d. 365 ¼ days

392. Which of these is the imaginary line that the Earth spins around to complete one day?

a. axis
b. orbit
c. poles
d. latitude

393. Which of the following refers to the spinning movement of the Earth on its axis?

a. tilting
b. orbiting
c. rotation
d. revolution

394. Which statement is true about the Earth’s movement?

a. Revolution causes day and night.
b. The Earth rotates in a counterclockwise direction when viewed from the northern polar star.
c. Seasonal changes are effects of the Earth’s rotation.
d. The movement of water in the seas and oceans is an effect of the Earth’s revolution.

395. Which statement is false about the Earth’s orbit?

a. The Earth’s orbit is slanted 23.5 degrees.
b. An orbit is an elliptical path around the sun.
c. An orbit is an imaginary route of the Earth around the sun.
d. As the Earth spins on its axis, it also travels around its orbit.

396. Which are the two seasons experienced in places near the equator?

a. wet and dry
b. fall and spring
c. dry and spring
d. summer and winter

397. Which of the following statements about the revolution of the Earth is correct?

a. As the Earth spins on its axis, it causes climate change.
b. As the Earth revolves around the sun, it causes day and night.
c. As the Earth revolves around the sun, it also rotates on its axis.
d. As the sun revolves around the Earth, it causes seasonal change.

398. What do you call the short climatic changes caused by the Earth’s tilted axis?

a. coriolis
b. monsoon
c. season
d. weather

399. Which of the following statements describe the outer planets?

a. They are large and made of rocks.
b. They are small and made of ice and gas.
c. They are large and made up mostly of gas.
d. They are solid and made up of rocks and metals.

400. Which of the following planets has the highest average surface temperature?

a. Mars
b. Venus
c. Jupiter
d. Mercury

401. How are Earth and Venus similar to each other?

a. Venus and Earth are Jovian planets.
b. Venus and Earth have almost the same size.
c. Venus and Earth have almost the same temperature.
d. Venus and Earth have the same distance from the Sun.

402. Which of the terrestrial planets is the biggest?

a. Mars
b. Earth
c. Venus
d. Mercury

403. Which of the following planets is farthest from the Sun?

a. Venus
b. Jupiter
c. Uranus
d. Neptune

404. Which among the four is the smallest?

a. Saturn
b. Jupiter
c. Uranus
d. Neptune

405. Which planet is the largest?

a. Mars
b. Earth
c. Jupiter
d. Uranus

406. Which among the planets have extensive and complex rings?

a. Saturn
b. Jupiter
c. Uranus
d. Neptune

407. Which of the following are the inner planets?

a. Mercury, Venus, Earth, Mars
b. Venus, Mars, Saturn, Uranus
c. Earth, Jupiter, Uranus, Neptune
d. Jupiter, Saturn, Uranus, Neptune

408. Which is Earth’s twin planet?

a. Uranus
b. Mars
c. Jupiter
d. Venus

409. Which is the seventh planet from the Sun?

a. Uranus
b. Mars
c. Jupiter
d. Venus

410. Which is known as the red planet?

a. Uranus
b. Mars
c. Jupiter
d. Venus

411. Which statement is false?

a. The inner planets are smaller than the outer planets.
b. The outer planets are bigger than the inner planets.
c. The inner planets have average temperatures above 0°C while the outer planets have average temperatures below 0°C.
d. None of the above

412. Which of the following statements correctly describes the inner planets?

a. They are small and made of ice and gas.
b. They are large and made up mostly of gas.
c. They are large and made of gases and metal.
d. They are solid and made up of rocks and metals.

413. In a total solar eclipse, _____.

a. the moon passes between the sun and the earth, blocking the sun
b. the sun is between the moon and the earth, blocking the moon
c. the earth is between the sun and the moon, blocking the sun
d. the sun is between the earth and the moon, blocking the earth

414. Why do the planets stay in their orbits as they revolve around the sun?

a. Because of the earth’s size
b. Because of the earth’s rotation
c. Because of the earth’s gravity
d. Because of the sun’s gravity

415. Which statement correctly describes the atmosphere of each planet?

a. The atmosphere of Venus is mostly carbon dioxide.
b. The atmosphere of Mercury is mostly nitrogen.
c. The atmosphere of Earth is mostly oxygen.
d. The atmosphere of Saturn is mostly helium.

416. Term used to describe the moon when it seems to be growing

a. crescent
b. gibbous
c. waning
d. waxing

417. Term used to describe the moon when its lighted part is becoming smaller

a. crescent
b. gibbous
c. waning
d. waxing

418. Term used to describe the moon when more than half of it is illuminated, but not fully

a. crescent
b. gibbous
c. waning
d. waxing

419. Term used to describe the moon when less than half of it is illuminated, but not totally dark

a. crescent
b. gibbous
c. waning
d. waxing

420. What phase will the moon be if it is between the earth and the sun?

a. full moon
b. new moon
c. first quarter
d. last quarter

421. What phase will the moon be if the earth is between it and the sun?

a. full moon
b. new moon
c. first quarter
d. last quarter

422. In which phase does the moon appear dark?

a. full moon
b. new moon
c. first quarter
d. last quarter

423. A constellation is a group of visible ______ that appear to form a pattern when viewed from Earth.

a. lights
b. planets
c. comets
d. stars

424. Groups of stars that are not constellations by themselves but belong to a constellation are called _____.

a. asterisms
b. galaxies
c. nebulae
d. shooting stars

425. The stars with the highest temperature appear _____.

a. blue
b. yellow
c. orange
d. red

426. A star’s lifespan is primarily determined by its _____.

a. gas component
b. color
c. mass
d. distance from a black hole

427. Which gas powers the nuclear reactions within stars that make them shine brightly?

a. carbon
b. hydrogen
c. helium
d. oxygen

428. Which of the following statements is correct?

a. Smaller stars run out of fuel faster and tend to have shorter lifespans.
b. Larger stars have more fuel and tend to have longer lifespans.
c. If an exploding star is massive enough, it may form a black hole.
d. All of the above

429. _____ is the process by which plants release water from their leaves.

a. Evaporation
b. Condensation
c. Precipitation
d. Transpiration

430. _____ is the process by which condensed water vapor falls back to the Earth in the form of rain, hail, snow or sleet.

a. Evaporation
b. Condensation
c. Precipitation
d. Transpiration

431. _____ is the process by which water vapor (gas) changes into tiny droplets of liquid water in the atmosphere.

a. Evaporation
b. Condensation
c. Precipitation
d. Respiration

432. _____ is the process by which humans and animals breathe out water particles through their lungs and when they perspire.

a. Respiration
b. Perspiration
c. Precipitation
d. Transpiration

433. Which of these temperatures is the coldest?

a. 10°C
b. 20°C
c. 37°C
d. 45°C

434. High, wispy, feathery clouds

a. cirrus
b. cumulus
c. nimbus
d. stratus

435. Clouds that tend to produce precipitation

a. cirrus
b. cumulus
c. nimbus
d. stratus

436. Clouds that look like puffs of cotton and are usually spotted in fair weather

a. cirrus
b. cumulus
c. nimbus
d. stratus

437. Low-lying uniform grayish clouds that often cover the entire sky

a. cirrus
b. cumulus
c. nimbus
d. stratus

438. This refers to the hotness or coldness of the environment.

a. humidity
b. pressure
c. temperature
d. weather

439. This refers to the amount of moisture in the air.

a. humidity
b. pressure
c. temperature
d. weather

440. This refers to the weight of force that is produced when something presses or pushes against something else.

a. humidity
b. pressure
c. temperature
d. weather

441. Which of these weather instruments measures temperature?

a. anemometer
b. barometer
c. hygrometer
d. thermometer

442. Which of these weather instruments measures wind speed and pressure?

a. anemometer
b. barometer
c. hygrometer
d. wind vane

443. Which of these weather instruments indicates the direction of the wind?

a. anemometer
b. barometer
c. hygrometer
d. wind vane

444. Which of these weather instruments measures the humidity of air?

a. anemometer
b. barometer
c. hygrometer
d. rain gauge

445. Which of these weather instruments measures atmospheric pressure?

a. anemometer
b. barometer
c. hygrometer
d. wind vane

446. Which of these weather instruments measures the amount of liquid precipitation that has fallen over a specific area within a specific time period?

a. anemometer
b. barometer
c. hygrometer
d. rain gauge

447. Which of the following statements is false?

a. Tropical cyclones that form in the Atlantic and Eastern Pacific Oceans are called hurricanes.
b. Tropical cyclones that form in the Western Pacific Ocean are called typhoons.
c. The source of heat of tropical cyclones is warm air from the ocean.
d. None – all are correct.

448. The kind of soil that is sticky when wet and has the finest texture is _____.

a. clay
b. loam
c. humus
d. sand

449. _____ is a mixture of sand and clay.

a. Clay
b. Loam
c. Humus
d. Sand

450. _____ is a dark-colored organic material made up of decaying plants and animals. It is found in the uppermost layer of the soil.

a. Clay
b. Loam
c. Humus
d. Sand

451. The particles of this type of soil are coarse and loose.

a. clay
b. loam
c. humus
d. sand

452. This layer of soil is rich in humus and minerals.

a. topsoil
b. subsoil
c. parent rock
d. bedrock

453. This layer of soil is rich in minerals. It contains less humus but can hold more water than the layer above it.

a. topsoil
b. subsoil
c. parent rock
d. bedrock

454. This layer is made up of a large solid mass of rock or undisturbed large boulders.

a. topsoil
b. subsoil
c. parent rock
d. bedrock

455. The upper layers develop from this layer.

a. topsoil
b. subsoil
c. parent rock
d. bedrock

456. _____ is the wearing away or breaking of rocks into fragments.

a. Erosion
b. Siltation
c. Sedimentation
d. Weathering

457. A type of weathering that involves a change in the composition of the rock

a. physical weathering
b. chemical weathering
c. abrasion
d. thermal expansion

458. The following are mechanical weathering processes except _____.

a. abrasion
b. exfoliation
c. oxidation
d. thermal expansion

459. The transfer of solid and rock fragments from one place to another

a. erosion
b. siltation
c. sedimentation
d. weathering

460. Contour plowing, crop rotation, and strip cropping are all strategies for preventing _____.

a. erosion
b. siltation
c. sedimentation
d. weathering

461. This is one of the methods for preventing soil erosion.

a. riprapping
b. terracing
c. windbreaks
d. all of the above