ASVAB General Science Practice Test: 100 Questions

Official General Science Scope

The official ASVAB subtests page describes General Science, abbreviated GS, as knowledge of physical and biological sciences. The official General Science sample page describes the section as focused on the ability to solve basic science problems. That means this is not an advanced chemistry, physics or biology final exam. It is a broad applied-science check: can you recognize basic facts, connect cause and effect, understand common science vocabulary, and choose the best answer quickly?

For a beginner, the fastest way to study is to group the official description into practical buckets: life science, earth and space science, physical science, basic chemistry, and scientific reasoning. Those buckets are not a separate official score report. They are a study structure. The official score report gives a General Science standard score, not separate biology or chemistry scores. This page uses the buckets so a student can see what they missed and fix the weak area.

How to Use This Practice Test

If you know nothing about ASVAB General Science, do not start by timing all 100 questions. First, take 20 questions slowly and read every explanation. Then take a timed 15-question set. Then use the error log to decide which science bucket needs review. The goal is not to memorize this page. The goal is to learn enough basic science that a new question feels familiar.

1. Read the question and answer choices before opening the explanation.
2. Choose one answer. Do not leave it blank.
3. Open the explanation and write the missed concept in your notes.
4. After every 25 questions, count misses by topic.
5. Redo only missed questions after 24 hours.
6. Before test day, do timed 15-question and 25-question sets.

General Science is not part of the AFQT formula, but it can matter for broader ASVAB profiles and military job qualification composites depending on branch and job. Use the ASVAB Score Calculator and ASVAB Score Guide after you have official scores. Use the ASVAB Study Guide if you need the full test process from zero.

Zero-Start Review Before the Practice Test

If you are new to ASVAB General Science, the biggest mistake is trying to study every science word at the same depth. General Science rewards broad recognition. You need to know enough biology to recognize what cells, organs, heredity and ecosystems do. You need enough earth science to explain weather, rocks, tides and seasons. You need enough physical science to connect motion, force, energy, heat, waves, electricity and magnetism. You need enough chemistry to tell atoms, molecules, mixtures, solutions, acids, bases, physical changes and chemical changes apart. You also need enough scientific reasoning to read a short experiment and identify variables, controls and evidence.

Use this review as a warm-up before the 100 questions. It is written in the same plain, applied style that helps on broad military entrance testing: concept first, common trap second, practice behavior third. Do not try to memorize paragraphs. Turn each paragraph into a short note, then answer the practice questions without looking back.

Step 1: Read Life Science as Systems, Not Loose Facts

Life science questions usually ask what a structure does or how living things interact. Start with the cell. The nucleus stores genetic instructions. The cell membrane controls movement into and out of the cell. Mitochondria help release usable energy from food. Chloroplasts in plant cells capture light energy for photosynthesis. Ribosomes build proteins. A beginner does not need college cell biology; you need a working map. When a question names a structure, ask, "Is this about information, energy, boundary control, food-making or protein-building?" That one habit eliminates many wrong choices.

Move from cells to body systems. The circulatory system moves blood. The respiratory system exchanges oxygen and carbon dioxide. The digestive system breaks food into usable nutrients. The kidneys help remove wastes and regulate water balance. The nervous system sends signals. The immune system defends against disease. If a question mentions oxygen in blood, think red blood cells and hemoglobin. If it mentions air sacs, think alveoli. If it mentions filtering blood, think kidneys. These are not random facts; each system has a job.

Then connect organisms to ecosystems. Producers make food, usually by photosynthesis. Consumers eat other organisms. Decomposers break down dead matter and recycle nutrients. Herbivores eat plants, carnivores eat animals, and omnivores eat both. Predator-prey questions usually identify who eats and who is eaten. Energy moves through food chains, but matter cycles through ecosystems. That difference is important: sunlight can enter a food web as energy, while atoms such as carbon and nitrogen are reused.

Common life science traps include choosing a familiar word that does not match the job. For example, the heart does not filter urine, the lungs do not pump blood through arteries, and DNA does not directly digest food. In practice, underline the action word: carry, filter, exchange, inherit, protect, break down, produce. The action usually points to the answer.

Step 2: Treat Earth and Space Science as Cause and Effect

Earth and space science questions often test why something happens. Weathering breaks rocks down. Erosion moves the broken material. Sedimentary rocks can form when layers of sediment compact and cement. Igneous rocks form from cooled magma or lava. Metamorphic rocks form when existing rock is changed by heat and pressure. A simple rock-cycle question is usually asking for the cause: cooling, layering, or heat and pressure.

The water cycle is another cause-and-effect chain. Evaporation changes liquid water into vapor. Condensation changes vapor into droplets or ice crystals. Precipitation returns water to the ground as rain, snow, sleet or hail. Runoff moves water across land, while infiltration moves water into soil and groundwater. If a question says water vapor cools and forms clouds, condensation is the best answer. If it says sunlight changes liquid water into vapor, evaporation is the best answer.

Weather questions use pressure, temperature and moisture. A barometer measures air pressure. Low pressure often allows air to rise and can be associated with clouds or storms. High pressure often connects with sinking air and calmer conditions. The atmosphere is mostly nitrogen, with oxygen second. The ozone layer helps absorb ultraviolet radiation. Greenhouse gases absorb and re-emit infrared heat. These facts are basic, but ASVAB-style questions can phrase them as practical situations rather than dictionary definitions.

Space questions usually involve motion and gravity. Earth rotates on its axis, producing day and night. Earth revolves around the Sun, producing a year. Seasons are mainly caused by Earth's tilted axis as Earth moves around the Sun, not by Earth being much closer to the Sun in summer. Moon phases happen because we see different portions of the Moon's sunlit half. Tides are caused mostly by the Moon's gravity, with the Sun also contributing. Gravity keeps planets in orbit. For a beginner, the key is to match each event with the motion that causes it: rotation, revolution, tilt, gravity, or changing viewing angle.

Step 3: Learn Physical Science Through Units and Relationships

Physical science feels easier when you attach each idea to a relationship. Force relates to mass and acceleration, often written as F=ma. Speed relates to distance and time. Density is mass divided by volume. Pressure is force divided by area. Work happens when force moves an object through a distance. Power is how quickly work is done or energy is transferred. You do not need a long formula sheet for basic General Science, but you do need to recognize which relationship a question describes.

Motion questions often test vocabulary. Inertia is resistance to change in motion. Acceleration is a change in velocity. Friction opposes motion between surfaces. Newton's third law says interacting objects exert paired forces on each other. Energy questions divide into stored energy and motion energy: potential energy is stored, kinetic energy is motion. Heat questions divide into conduction, convection and radiation. Conduction is direct contact, convection is movement of a fluid, and radiation travels by electromagnetic waves. If a hot pan handle warms your hand, think conduction. If warm air rises, think convection. If sunlight warms your face, think radiation.

Waves and electricity also follow simple clues. Sound needs a medium such as air, water or solid matter. Light can travel through a vacuum. Higher sound frequency usually means higher pitch. Electric current is the flow of charge. A closed circuit provides a complete path. Conductors allow current to flow more easily, while insulators resist it. Opposite magnetic poles attract, and like poles repel. These are short ideas, but they come up in many applied science questions.

Physical science traps usually confuse everyday language with science language. "Work" in physics is not just effort; force must move an object through distance. "Power" is not just strength; it is the rate of doing work. "Current" is not voltage; it is moving charge. When choices look similar, ask which word is being defined by the situation.

Step 4: Keep Chemistry at the General-Science Level

Basic chemistry starts with matter. An atom is the basic unit of an element. Protons are positive, electrons are negative and neutrons are neutral. The atomic number equals the number of protons. A molecule is made of atoms bonded together. A compound contains two or more different elements chemically combined in fixed proportions. A mixture is physically combined and can often be separated by physical methods. A solution is a uniform mixture, such as salt dissolved in water.

pH is a common beginner concept. A pH below 7 is acidic, a pH near 7 is neutral, and a pH above 7 is basic. Do not overcomplicate this for General Science practice. If the question asks whether lemon juice is acidic or whether soap is basic, it is checking the direction of the scale. You may also see physical versus chemical changes. A physical change changes form or state without making a new substance, such as melting ice. A chemical change produces new substances, such as burning, rusting or reacting. Conservation of mass means matter is not created or destroyed in ordinary chemical reactions; the atoms are rearranged.

Chemistry questions can be solved by asking, "Did the identity change?" If ice becomes water, the identity is still water. If iron rusts, new iron oxide forms. If salt dissolves in water, the salt and water are mixed in a solution, but the process is not the same as forming a new element. This identity question is one of the fastest ways to avoid chemistry traps.

Step 5: Use Scientific Reasoning to Rescue Unfamiliar Questions

Scientific reasoning matters because not every question is pure recall. A hypothesis is a testable explanation or prediction. The independent variable is what the investigator changes. The dependent variable is what gets measured. Controlled variables are kept the same so the test is fair. A control group gives a baseline for comparison. Repeated trials improve reliability by reducing the effect of random error. A conclusion should follow from evidence, not from a preferred outcome.

If a question describes an experiment, identify the changed factor first. Then identify the measured result. For example, if a student changes the amount of fertilizer and measures plant height, fertilizer amount is the independent variable and plant height is the dependent variable. The same type of plant, same soil, same water and same light should be controlled variables. That logic works across biology, chemistry and physical science questions.

Graphs and data questions usually ask you to read carefully, not calculate heavily. The independent variable is often on the x-axis, and the dependent variable is often on the y-axis. A trend is a pattern in the data. A correlation means two variables change together, but correlation alone does not prove causation. If results are inconsistent, a scientific next step is to repeat the experiment, check the method, review measurements and look for uncontrolled variables. Guessing that the preferred result must be correct is not scientific reasoning.

Step 6: Turn This Page Into a Timed Training Routine

For the first pass, answer questions 1-25 slowly and open every explanation. These questions lean toward life science and earth science, so write down missed vocabulary. For the second pass, answer questions 26-50 and time yourself gently. These questions move through water cycle, space, weather and early physical science. For the third pass, answer questions 51-75 under tighter timing. These questions focus on heat, waves, electricity and chemistry. For the fourth pass, answer questions 76-100 and pay attention to experiment design and reasoning.

After each pass, do not simply record a percent. Build an error log with three columns: missed topic, why the wrong answer looked tempting, and the corrected rule. A useful entry looks like this: "Convection: I chose conduction because both involve heat; rule is convection uses moving fluid." This style fixes the exact confusion instead of creating a long list of topics you already half understand.

Once you can answer most items slowly, create official-style timed sets. For CAT-ASVAB practice, choose 15 mixed questions and give yourself about 12 minutes. For paper-and-pencil practice, choose 25 mixed questions and give yourself about 11 minutes. Do not use this timing on your very first attempt. Timing is useful after the concepts are familiar. Early speed practice can teach you to rush through the same misunderstandings.

Finally, keep intent separation clear while you study. This page is for General Science practice. Use the main ASVAB Study Guide for the full exam process, the ASVAB Score Guide for score interpretation, the AFQT Score Calculator for entrance percentile context, and the ASVAB Scores by Military Branch page when comparing public branch-level score context. Keeping each resource in its lane helps both students and search engines understand the purpose of each page.

ASVAB General Science Practice Test: 100 Questions

Answer all questions before checking explanations if you want a realistic practice score. If you are learning from zero, open each explanation right after answering and write down the concept in your own words.

1. Which cell structure controls most cell activities and contains DNA?
   1. Ribosome
   2. Nucleus
   3. Cell membrane
   4. Mitochondrion
   Answer and explanation

   Answer: B. The nucleus stores DNA and helps control cell activities such as growth and reproduction.

2. Plants use sunlight, water and carbon dioxide to make food during which process?
   1. Respiration
   2. Fermentation
   3. Photosynthesis
   4. Digestion
   Answer and explanation

   Answer: C. Photosynthesis uses light energy to make glucose and releases oxygen as a byproduct.

3. Which organelle releases usable energy from food molecules in many cells?
   1. Mitochondrion
   2. Vacuole
   3. Cell wall
   4. Chloroplast
   Answer and explanation

   Answer: A. Mitochondria help convert chemical energy in food into usable cellular energy.

4. What is the main function of DNA?
   1. Break down fats
   2. Carry hereditary information
   3. Transport oxygen
   4. Fight infections directly
   Answer and explanation

   Answer: B. DNA contains genetic instructions that are passed from parents to offspring.

5. Red blood cells mainly help the body by transporting which substance?
   1. Oxygen
   2. Bile
   3. Insulin
   4. Urine
   Answer and explanation

   Answer: A. Red blood cells contain hemoglobin, which binds and carries oxygen through the blood.

6. Which organ pumps blood through the circulatory system?
   1. Liver
   2. Heart
   3. Kidney
   4. Stomach
   Answer and explanation

   Answer: B. The heart is a muscular pump that moves blood through arteries, veins and capillaries.

7. Gas exchange in the lungs mainly occurs in tiny sacs called what?
   1. Neurons
   2. Alveoli
   3. Tendons
   4. Villi
   Answer and explanation

   Answer: B. Alveoli provide a large surface area for oxygen and carbon dioxide exchange.

8. Which organs filter wastes from the blood and help make urine?
   1. Kidneys
   2. Lungs
   3. Pancreas
   4. Spleen
   Answer and explanation

   Answer: A. Kidneys filter blood, regulate water balance and remove wastes in urine.

9. What do plant roots mainly absorb from soil?
   1. Oxygen and sugar
   2. Water and minerals
   3. Carbon dioxide and light
   4. Proteins and fats
   Answer and explanation

   Answer: B. Roots take in water and dissolved minerals that plants need for growth.

10. In a food chain, organisms that make their own food are called what?
    1. Consumers
    2. Producers
    3. Parasites
    4. Predators
    Answer and explanation

    Answer: B. Producers, such as plants and algae, make food using sunlight or chemical energy.

11. Which organisms break down dead material and recycle nutrients?
    1. Decomposers
    2. Primary consumers
    3. Herbivores
    4. Pollinators
    Answer and explanation

    Answer: A. Decomposers such as fungi and bacteria break down dead organisms and waste.

12. A wolf eating a rabbit is an example of what relationship?
    1. Predator-prey
    2. Mutualism
    3. Competition only
    4. Photosynthesis
    Answer and explanation

    Answer: A. The wolf is the predator, and the rabbit is the prey.

13. What is the main purpose of a vaccine?
    1. Provide oxygen to cells
    2. Stimulate immune protection
    3. Digest carbohydrates
    4. Replace red blood cells
    Answer and explanation

    Answer: B. Vaccines train the immune system to recognize a disease-causing agent.

14. Bacteria are best described as what?
    1. Single-celled organisms
    2. Nonliving minerals
    3. Only plant cells
    4. Large multicellular animals
    Answer and explanation

    Answer: A. Bacteria are single-celled organisms; some are harmful, while many are useful or harmless.

15. A virus usually reproduces only when it does what?
    1. Crystallizes in salt water
    2. Enters a host cell
    3. Forms a rock layer
    4. Absorbs sunlight directly
    Answer and explanation

    Answer: B. Viruses need host cells to copy themselves.

16. The body's ability to maintain stable internal conditions is called what?
    1. Homeostasis
    2. Metamorphism
    3. Condensation
    4. Magnetism
    Answer and explanation

    Answer: A. Homeostasis includes keeping temperature, water balance and blood chemistry within useful ranges.

17. Which process produces sex cells with half the usual number of chromosomes?
    1. Mitosis
    2. Meiosis
    3. Osmosis
    4. Evaporation
    Answer and explanation

    Answer: B. Meiosis produces sperm or egg cells with half the chromosome number.

18. Which structure helps control what enters and leaves a cell?
    1. Cell membrane
    2. Ribosome
    3. Chromosome
    4. Nucleolus
    Answer and explanation

    Answer: A. The cell membrane is a boundary that helps regulate movement into and out of the cell.

19. Which term describes animals that eat only plants?
    1. Carnivores
    2. Herbivores
    3. Omnivores
    4. Decomposers
    Answer and explanation

    Answer: B. Herbivores eat plants; carnivores eat animals; omnivores eat both.

20. In a food chain, a rabbit that eats grass is usually a what?
    1. Producer
    2. Primary consumer
    3. Decomposer
    4. Secondary consumer
    Answer and explanation

    Answer: B. A primary consumer eats producers such as grass.

21. What is the most abundant gas in Earth's atmosphere?
    1. Oxygen
    2. Nitrogen
    3. Carbon dioxide
    4. Argon
    Answer and explanation

    Answer: B. Nitrogen makes up most of Earth's atmosphere.

22. The breaking down of rock into smaller pieces is called what?
    1. Weathering
    2. Condensation
    3. Deposition
    4. Conduction
    Answer and explanation

    Answer: A. Weathering breaks rock down; erosion moves the broken material.

23. Rock formed when melted material cools and hardens is what type?
    1. Sedimentary
    2. Igneous
    3. Metamorphic
    4. Organic
    Answer and explanation

    Answer: B. Igneous rock forms from cooled magma or lava.

24. Which rock type often forms from layers of compacted sediment?
    1. Sedimentary
    2. Igneous
    3. Metamorphic
    4. Metallic
    Answer and explanation

    Answer: A. Sedimentary rock commonly forms from deposited sediment that becomes compacted and cemented.

25. Heat and pressure can change existing rock into which type?
    1. Metamorphic
    2. Volcanic only
    3. Atmospheric
    4. Fossil fuel only
    Answer and explanation

    Answer: A. Metamorphic rock forms when existing rock changes under heat and pressure.

26. Liquid water changing into water vapor is called what?
    1. Condensation
    2. Evaporation
    3. Precipitation
    4. Freezing
    Answer and explanation

    Answer: B. Evaporation is the change from liquid water to water vapor.

27. Clouds commonly form when water vapor cools and does what?
    1. Condenses
    2. Burns
    3. Magnetizes
    4. Ionizes completely
    Answer and explanation

    Answer: A. Condensation changes water vapor into tiny liquid droplets or ice crystals.

28. Ocean tides are caused mostly by the gravitational pull of what?
    1. The Moon
    2. Clouds
    3. Volcanoes
    4. Earth's core only
    Answer and explanation

    Answer: A. The Moon's gravity is the main cause of Earth's tides.

29. Earth's rotation on its axis causes which cycle?
    1. Day and night
    2. The seasons by itself
    3. Ocean salinity
    4. Rock formation
    Answer and explanation

    Answer: A. Earth rotates once about every 24 hours, producing day and night.

30. Earth's revolution around the Sun takes about how long?
    1. One day
    2. One month
    3. One year
    4. Ten years
    Answer and explanation

    Answer: C. Earth completes one orbit around the Sun in about one year.

31. Seasons on Earth are mainly caused by what?
    1. Earth's tilted axis
    2. Changing distance from the Moon
    3. Ocean tides only
    4. Cloud color
    Answer and explanation

    Answer: A. Earth's axial tilt changes sunlight angle and day length through the year.

32. Moon phases are mainly caused by what?
    1. Earth's shadow every night
    2. Changing positions of the Sun, Earth and Moon
    3. Changes in Moon size
    4. Clouds blocking the Moon
    Answer and explanation

    Answer: B. We see different portions of the Moon's sunlit half as positions change.

33. Which energy source is renewable?
    1. Coal
    2. Oil
    3. Solar energy
    4. Natural gas
    Answer and explanation

    Answer: C. Solar energy is renewable because sunlight is naturally replenished.

34. Coal is considered nonrenewable mainly because it does what?
    1. Forms very slowly over geologic time
    2. Contains no carbon
    3. Is made daily by plants
    4. Cannot release heat
    Answer and explanation

    Answer: A. Coal forms over millions of years, so it is not replaced quickly on human time scales.

35. Greenhouse gases help warm Earth by trapping what?
    1. Some outgoing heat energy
    2. All incoming visible light
    3. Only ocean salt
    4. Only sound waves
    Answer and explanation

    Answer: A. Greenhouse gases absorb and re-emit infrared heat energy.

36. A barometer measures which weather-related quantity?
    1. Air pressure
    2. Wind direction only
    3. Rain acidity only
    4. Soil texture
    Answer and explanation

    Answer: A. A barometer measures atmospheric pressure.

37. Low air pressure is often associated with what kind of weather?
    1. Clear skies only
    2. Clouds and storms
    3. No wind ever
    4. Permanent drought
    Answer and explanation

    Answer: B. Low pressure often allows air to rise, cool and form clouds or storms.

38. Which instrument detects and records earthquake waves?
    1. Thermometer
    2. Seismograph
    3. Barometer
    4. Hygrometer
    Answer and explanation

    Answer: B. A seismograph records seismic waves from earthquakes.

39. The ozone layer helps protect life by absorbing much of which radiation?
    1. Ultraviolet radiation
    2. Sound radiation
    3. Magnetic gravity
    4. Ocean heat only
    Answer and explanation

    Answer: A. Ozone absorbs much of the Sun's harmful ultraviolet radiation.

40. What force keeps planets in orbit around the Sun?
    1. Friction
    2. Gravity
    3. Air pressure
    4. Static electricity only
    Answer and explanation

    Answer: B. Gravity attracts planets toward the Sun and helps maintain their orbits.

41. According to Newton's second law, force equals mass times what?
    1. Volume
    2. Acceleration
    3. Temperature
    4. Density
    Answer and explanation

    Answer: B. Newton's second law is commonly written as F=ma.

42. An object resisting a change in motion demonstrates which property?
    1. Inertia
    2. Evaporation
    3. Condensation
    4. Solubility
    Answer and explanation

    Answer: A. Inertia is the tendency of an object to resist changes in motion.

43. Which force opposes motion between surfaces in contact?
    1. Friction
    2. Buoyancy only
    3. Radiation
    4. Photosynthesis
    Answer and explanation

    Answer: A. Friction acts against relative motion between touching surfaces.

44. Acceleration is best described as a change in what?
    1. Velocity over time
    2. Mass only
    3. Color only
    4. Volume only
    Answer and explanation

    Answer: A. Acceleration is the rate at which velocity changes.

45. Stored energy due to position is called what?
    1. Kinetic energy
    2. Potential energy
    3. Thermal equilibrium
    4. Magnetic field only
    Answer and explanation

    Answer: B. Potential energy is stored energy, such as energy from height or compression.

46. Energy of motion is called what?
    1. Kinetic energy
    2. Chemical inactivity
    3. Potential energy only
    4. Insulation
    Answer and explanation

    Answer: A. Moving objects have kinetic energy.

47. A lever, pulley or inclined plane is an example of what?
    1. Simple machine
    2. Mixture
    3. Hormone
    4. Galaxy
    Answer and explanation

    Answer: A. Simple machines help change the size or direction of a force.

48. Density is calculated as mass divided by what?
    1. Temperature
    2. Volume
    3. Speed
    4. Time
    Answer and explanation

    Answer: B. Density equals mass per unit volume.

49. An object floats in water when it is generally what compared with water?
    1. Less dense
    2. More dense
    3. Hotter only
    4. Magnetic only
    Answer and explanation

    Answer: A. Objects less dense than the fluid they displace tend to float.

50. Heat transfer through direct contact is called what?
    1. Conduction
    2. Convection
    3. Radiation
    4. Reflection
    Answer and explanation

    Answer: A. Conduction transfers heat through direct contact between particles or objects.

51. Heat transfer by movement of a liquid or gas is called what?
    1. Convection
    2. Refraction
    3. Condensation only
    4. Magnetism
    Answer and explanation

    Answer: A. Convection occurs when warmer fluid moves and carries heat.

52. Heat transfer by electromagnetic waves is called what?
    1. Conduction
    2. Radiation
    3. Freezing
    4. Sedimentation
    Answer and explanation

    Answer: B. Radiation can transfer energy through empty space, as sunlight does.

53. Sound waves require what in order to travel?
    1. A material medium
    2. A vacuum only
    3. No particles at all
    4. A chemical reaction only
    Answer and explanation

    Answer: A. Sound needs matter such as air, water or solid material to carry vibrations.

54. Light travels fastest through which environment?
    1. Vacuum
    2. Thick glass
    3. Muddy water
    4. Steel
    Answer and explanation

    Answer: A. Light travels fastest in a vacuum and slows in materials.

55. For sound, higher frequency usually means higher what?
    1. Pitch
    2. Mass
    3. Density
    4. Boiling point
    Answer and explanation

    Answer: A. Higher-frequency sound waves are heard as higher pitch.

56. Electric current is the flow of what?
    1. Electric charge
    2. Liquid water only
    3. Air pressure
    4. Heatless atoms
    Answer and explanation

    Answer: A. Current is the flow of electric charge, often electrons in a wire.

57. A complete path for electric current is called what?
    1. Closed circuit
    2. Open fossil
    3. Weather front
    4. Food web
    Answer and explanation

    Answer: A. A closed circuit provides a continuous path for current.

58. A material that resists the flow of electric current is a what?
    1. Conductor
    2. Insulator
    3. Solvent
    4. Catalyst
    Answer and explanation

    Answer: B. Insulators, such as rubber or plastic, resist current flow.

59. Opposite magnetic poles do what?
    1. Attract
    2. Always vanish
    3. Become neutral atoms
    4. Stop gravity
    Answer and explanation

    Answer: A. Opposite magnetic poles attract; like poles repel.

60. At standard pressure, water freezes at what temperature?
    1. 0°C
    2. 37°C
    3. 100°C
    4. 212°C
    Answer and explanation

    Answer: A. Water freezes at 0°C, which is 32°F, at standard pressure.

61. Newton's third law is often summarized as what?
    1. Energy cannot move
    2. For every action, there is an equal and opposite reaction
    3. Atoms have no mass
    4. Heat only moves upward
    Answer and explanation

    Answer: B. Newton's third law describes paired forces between interacting objects.

62. In physics, work is done when a force moves an object through what?
    1. A distance
    2. A color change
    3. A chemical symbol
    4. A vacuum only
    Answer and explanation

    Answer: A. Work involves force applied through a distance in the direction of motion.

63. Power is the rate at which what is done or energy is transferred?
    1. Work
    2. Mass
    3. Density
    4. pH
    Answer and explanation

    Answer: A. Power measures how quickly work is done or energy is transferred.

64. Pressure is force divided by what?
    1. Area
    2. Color
    3. Temperature
    4. Frequency
    Answer and explanation

    Answer: A. Pressure equals force per unit area.

65. The basic unit of an element is a what?
    1. Atom
    2. Galaxy
    3. Tissue
    4. Organ
    Answer and explanation

    Answer: A. An atom is the smallest unit of an element that keeps that element's identity.

66. Which subatomic particle has a positive charge?
    1. Proton
    2. Electron
    3. Neutron
    4. Photon only
    Answer and explanation

    Answer: A. Protons are positively charged particles in the nucleus.

67. Which subatomic particle has a negative charge?
    1. Electron
    2. Proton
    3. Neutron
    4. Nucleus
    Answer and explanation

    Answer: A. Electrons have negative charge and occupy regions around the nucleus.

68. An element's atomic number equals its number of what?
    1. Protons
    2. Neutrons plus electrons only
    3. Molecules
    4. Energy levels only
    Answer and explanation

    Answer: A. Atomic number is defined by the number of protons in the nucleus.

69. Two or more atoms chemically bonded together form a what?
    1. Molecule
    2. Weather front
    3. Cell wall
    4. Lever
    Answer and explanation

    Answer: A. A molecule is made of atoms joined by chemical bonds.

70. A compound contains what?
    1. Two or more different elements chemically combined
    2. Only one type of atom uncombined
    3. Only rocks and minerals
    4. No atoms
    Answer and explanation

    Answer: A. A compound forms when different elements chemically bond in fixed proportions.

71. A mixture differs from a compound because its parts are what?
    1. Physically combined
    2. Always radioactive
    3. Always a single element
    4. Not made of matter
    Answer and explanation

    Answer: A. Mixture components are physically combined and can often be separated by physical methods.

72. A solution is best described as which kind of mixture?
    1. Homogeneous mixture
    2. Only a solid element
    3. Living tissue
    4. Magnetic field
    Answer and explanation

    Answer: A. A solution is uniform throughout, such as salt water after salt dissolves.

73. A substance with pH less than 7 is usually classified as what?
    1. Acid
    2. Base
    3. Neutral only
    4. Metal only
    Answer and explanation

    Answer: A. Acids have pH values below 7; neutral water is near pH 7.

74. A substance with pH greater than 7 is usually classified as what?
    1. Base
    2. Acid
    3. Neutron
    4. Vacuum
    Answer and explanation

    Answer: A. Bases have pH values above 7.

75. When salt dissolves in water, the result is usually a what?
    1. Solution
    2. New planet
    3. Pure element only
    4. Sound wave
    Answer and explanation

    Answer: A. Dissolved salt forms a uniform solution with water.

76. Which change produces a new substance?
    1. Chemical change
    2. Physical change
    3. Melting only
    4. Cutting paper only
    Answer and explanation

    Answer: A. Chemical changes produce new substances with different properties.

77. Ice melting into liquid water is mainly what type of change?
    1. Physical change
    2. Nuclear reaction
    3. Genetic mutation
    4. Chemical change into hydrogen
    Answer and explanation

    Answer: A. Melting changes state but the substance remains water.

78. In an ordinary chemical reaction, mass is generally what?
    1. Conserved
    2. Destroyed completely
    3. Changed into time
    4. Always doubled
    Answer and explanation

    Answer: A. The law of conservation of mass says matter is not created or destroyed in ordinary chemical reactions.

79. A catalyst affects a chemical reaction by doing what?
    1. Speeding it up without being used up
    2. Turning all acids into metals
    3. Stopping all motion
    4. Changing gravity
    Answer and explanation

    Answer: A. A catalyst increases reaction rate and is not consumed in the overall reaction.

80. A testable explanation for an observation is a what?
    1. Hypothesis
    2. Conclusion only
    3. Constant
    4. Unit
    Answer and explanation

    Answer: A. A hypothesis is a testable explanation or prediction.

81. In an experiment, the variable intentionally changed by the investigator is the what?
    1. Independent variable
    2. Dependent variable
    3. Control group
    4. Conclusion
    Answer and explanation

    Answer: A. The independent variable is deliberately changed to test its effect.

82. The variable measured in response to a change is the what?
    1. Dependent variable
    2. Independent variable
    3. Safety rule
    4. Constant unit
    Answer and explanation

    Answer: A. The dependent variable is the outcome measured in the experiment.

83. A control group is used mainly for what purpose?
    1. Comparison
    2. Random decoration
    3. Measuring time only
    4. Creating heat only
    Answer and explanation

    Answer: A. A control group provides a baseline for comparing experimental results.

84. Repeating trials in an experiment usually improves what?
    1. Reliability
    2. Guessing only
    3. Gravity
    4. Mass of Earth
    Answer and explanation

    Answer: A. Repeated trials reduce the effect of random error and improve reliability.

85. On a standard graph, the independent variable is usually placed on which axis?
    1. x-axis
    2. y-axis
    3. No axis
    4. Only the title
    Answer and explanation

    Answer: A. The independent variable is commonly placed on the horizontal x-axis.

86. The SI base unit commonly used for mass is the what?
    1. Kilogram
    2. Meter
    3. Second
    4. Kelvin only
    Answer and explanation

    Answer: A. The kilogram is the SI base unit for mass.

87. Which tool is used to view very small objects such as cells?
    1. Microscope
    2. Barometer
    3. Compass
    4. Seismograph
    Answer and explanation

    Answer: A. A microscope magnifies small objects that are difficult to see with the unaided eye.

88. Which tool measures temperature?
    1. Thermometer
    2. Balance
    3. Graduated cylinder only
    4. Voltmeter only
    Answer and explanation

    Answer: A. A thermometer measures temperature.

89. Why should safety goggles be worn during many lab activities?
    1. To protect the eyes
    2. To increase gravity
    3. To make acids harmless
    4. To measure pH directly
    Answer and explanation

    Answer: A. Goggles protect the eyes from splashes, particles and other hazards.

90. The mean of 4, 6 and 8 is what?
    1. 6
    2. 8
    3. 18
    4. 4
    Answer and explanation

    Answer: A. Add the values and divide by 3: (4+6+8)/3=6.

91. A scientific conclusion should be based mainly on what?
    1. Evidence
    2. Popularity
    3. Unrecorded guesses
    4. Color preference
    Answer and explanation

    Answer: A. Scientific conclusions should follow from evidence and observations.

92. If experimental results are inconsistent, what is usually a good next step?
    1. Repeat the experiment and check the procedure
    2. Ignore all data
    3. Change the answer without evidence
    4. Stop measuring units
    Answer and explanation

    Answer: A. Repeating trials and reviewing procedure can identify error or variability.

93. A scientific model is used mainly to do what?
    1. Represent or explain a system
    2. Guarantee perfect truth forever
    3. Replace all observations
    4. Eliminate variables
    Answer and explanation

    Answer: A. Models help represent systems, make predictions and explain relationships.

94. If two variables are correlated, what does that prove by itself?
    1. They are related, but one may not cause the other
    2. One must always cause the other
    3. Both are identical
    4. Measurements are impossible
    Answer and explanation

    Answer: A. Correlation alone does not prove causation.

95. When reading liquid volume in a graduated cylinder, you should read the meniscus how?
    1. At eye level
    2. From far above only
    3. Without looking at units
    4. Only after boiling it
    Answer and explanation

    Answer: A. Reading at eye level reduces parallax error.

96. The boiling point of a liquid can change when what changes?
    1. Air pressure
    2. Calendar month only
    3. Color of the container only
    4. Sound pitch only
    Answer and explanation

    Answer: A. Boiling point depends partly on external pressure.

97. Variables kept the same during an experiment are called what?
    1. Controlled variables
    2. Dependent variables only
    3. Final conclusions
    4. Units of error
    Answer and explanation

    Answer: A. Controlled variables are held constant so the test is fair.

98. A scientific theory is best described as what?
    1. A well-supported explanation of natural phenomena
    2. A random guess with no evidence
    3. A single measurement
    4. A lab safety tool
    Answer and explanation

    Answer: A. A scientific theory is a broad explanation supported by evidence from many tests.

99. Peer review in science usually means what?
    1. Other qualified scientists evaluate the work
    2. The public votes on the answer
    3. The author hides the method
    4. The experiment is skipped
    Answer and explanation

    Answer: A. Peer review lets other qualified people examine the methods, evidence and reasoning before work is accepted more broadly.

100. A student tests whether fertilizer affects plant height. Which plan is the best controlled experiment?
     1. Use the same type of plant and change only the fertilizer amount
     2. Change plant type, light, water and fertilizer at the same time
     3. Measure height once without recording conditions
     4. Use different pots and never compare results
     Answer and explanation

     Answer: A. A fair test changes the independent variable, fertilizer amount, while keeping other important conditions as similar as possible.

What Your Practice Result Means

This practice test does not produce an official ASVAB score. Official ASVAB scores use standard scoring and psychometric procedures. Use your result as a study signal. If you miss many questions in life science, review cells, organs, genetics and ecosystems. If earth science is weak, review atmosphere, weather, rocks, water cycle and space basics. If physical science is weak, review forces, energy, heat, waves, electricity and density. If chemistry and scientific reasoning are weak, review atoms, pH, mixtures, lab variables and graph reading.

Official Sources Used

The ASVAB structure, General Science description, test timing, CAT-ASVAB behavior and score context in this page were checked against official ASVAB and ASVAB CEP sources. The practice questions are original and are not official test questions.