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ASVAB General Science practice test
10 free questions · scored as you go · every answer explained
Life science, earth and space, and physical science: the facts a good high-school course covers. On the computer-based ASVAB you get 15 General Science questions in 12 minutes, about 48 seconds per question. It does not count toward your AFQT, but the services use it to qualify you for certain jobs.
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Practice scores from original questions, not official ASVAB scores. ASVAB Test is not affiliated with the U.S. Department of Defense.
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GSGeneral Science1 of 10
Which part of a cell releases most of the energy the cell uses?
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Answer: D. The mitochondria
Mitochondria carry out cellular respiration, breaking down glucose with oxygen to release energy as ATP. The nucleus stores DNA, the membrane controls what enters and leaves, and ribosomes build proteins.
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GSGeneral Science2 of 10
Which component of blood carries oxygen from the lungs to the rest of the body?
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Answer: A. Red blood cells
Red blood cells contain hemoglobin, an iron-rich protein that binds oxygen in the lungs and releases it in the tissues. White blood cells fight infection, platelets clot blood, and plasma is the liquid that carries everything.
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GSGeneral Science3 of 10
In the water cycle, what is the process called when liquid water becomes water vapor?
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Answer: C. Evaporation
Evaporation turns liquid water into vapor, usually powered by the Sun. Condensation is the reverse (vapor to liquid, forming clouds), precipitation is rain or snow falling, and infiltration is water soaking into the ground.
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GSGeneral Science4 of 10
Which planet is closest to the Sun?
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Answer: B. Mercury
From the Sun outward the planets run Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. Venus is second and also the hottest, thanks to its thick carbon dioxide atmosphere.
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GSGeneral Science5 of 10
Which particle in an atom carries a negative charge?
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Answer: D. The electron
Electrons are negative and orbit the nucleus. Protons are positive, neutrons are neutral, and together protons and neutrons make the nucleus positive overall.
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GSGeneral Science6 of 10
A rifle kicks backward against a shooter's shoulder when fired. Which principle explains the kick?
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Answer: A. For every action there is an equal and opposite reaction
Newton's third law: the rifle pushes the bullet forward, so the bullet pushes the rifle backward with equal force. The first law is inertia and the second is F = ma; conservation of energy is a separate principle.
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GSGeneral Science7 of 10
During photosynthesis, which gas do green plants take in from the air?
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Answer: A. Carbon dioxide
Plants take in carbon dioxide and water and use sunlight to make glucose, releasing oxygen as a byproduct. Animals do the reverse in respiration: take in oxygen, give off carbon dioxide.
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GSGeneral Science8 of 10
A fast-moving cold front passes through an area. What weather does it most typically bring as it arrives?
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Answer: C. Brief heavy showers or thunderstorms, then cooler, clearer air
A cold front wedges under warm air and lifts it quickly, building towering clouds, showers or thunderstorms along a narrow band. Behind the front, air turns cooler and skies clear. Long steady drizzle is typical of a warm front.
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GSGeneral Science9 of 10
Which vitamin does the human body make when skin is exposed to sunlight?
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Answer: C. Vitamin D
Sunlight on skin converts a cholesterol compound into vitamin D, which helps the body absorb calcium for strong bones. Vitamin C comes from fruits and vegetables, A from sources like carrots and liver, and B12 from animal products.
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GSGeneral Science10 of 10
Why can't sound travel through the vacuum of space?
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Answer: B. Sound waves need matter to travel through
Sound is a vibration passed between particles, so it needs a medium such as air, water or steel. A vacuum has essentially no particles to vibrate. Light, by contrast, is an electromagnetic wave and crosses empty space easily.
What General Science covers
The facts and methods behind the questions, from the app's study notes. Questions on test day are different, but they test the same things.
Life science
Life science at good-high-school depth: cells and genetics, the major human body systems, nutrition, and how living things relate to each other.
- Cells. The nucleus holds DNA; mitochondria release energy (ATP); ribosomes build proteins; the membrane controls what enters. Mitosis copies a cell into two identical cells; meiosis makes sex cells with half the chromosomes.
- Body systems in one line each. Heart and vessels move blood; alveoli in the lungs swap oxygen for carbon dioxide; digestion starts in the mouth and absorbs in the small intestine; kidneys filter blood; neurons carry signals; marrow makes blood cells; the pancreas makes insulin.
- Nutrition numbers. Fat has 9 calories per gram; protein and carbs 4. Iron deficiency causes anemia, vitamin C scurvy, vitamin D (from sunlight) rickets, iodine goiter.
- Genetics. A dominant allele shows with one copy; recessive traits need two and can skip generations through carriers.
- Ecology. Food chains start with producers (plants). Mutualism helps both species; parasitism helps one at the other’s cost. Mammals nurse young; reptiles are cold-blooded; amphibians live in water and on land.
Earth and space science
Earth and space: the planet’s structure and rocks, weather and climate, and the solar system.
- Earth’s layers and plates. Crust, mantle, liquid outer core, solid inner core. Earthquakes cluster where tectonic plates grind past each other. Igneous rock cools from magma; sedimentary compresses in layers; metamorphic forms under heat and pressure.
- Weather. A cold front brings brief storms then clear, cooler air; a warm front brings long steady rain. Falling barometer = storm coming. Cumulonimbus clouds make thunderstorms. Relative humidity is the share of vapor the air could hold; at 100% it condenses.
- Hurricanes and storms. Hurricanes feed on warm ocean water and die over land. The ozone layer absorbs ultraviolet light; it does not trap heat (that is the greenhouse effect).
- Sun, Moon and seasons. Seasons come from Earth’s 23.5° tilt, not distance from the Sun. Moon phases are the angle we view its sunlit half; tides follow the Moon’s gravity, about two highs a day. Planet order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
Physical science
Physical science: matter and chemistry basics, forces and energy, waves and heat, and how science measures things.
- Matter. Atoms: protons (+) and neutrons in the nucleus, electrons (−) around it. Compounds are chemically bonded (water); mixtures are not (salt water). Rusting is a chemical change; melting is physical. pH below 7 is acid, above 7 is base.
- Forces and energy. Newton: (1) inertia, (2) F = ma, (3) action-reaction (a rifle’s kick). Mass never changes; weight is gravity’s pull on it. Raised water stores potential energy; moving water has kinetic energy. Speed = distance ÷ time.
- Heat, light, sound. Heat moves by conduction (contact), convection (fluid), radiation (waves). Evaporation cools. Sound needs a medium and crawls (~340 m/s); light needs none and flies (~300,000 km/s) — flash first, thunder later. Like magnetic poles repel.
- Measurement and method. Meter (length), liter (volume), gram (mass), newton (force). Water freezes 0 °C / 32 °F, boils 100 °C / 212 °F. A hypothesis is a testable prediction; the control group gets no treatment and sets the baseline.
Keep going in the app. All 62 General Science questions, practice that brings back the ones you miss, and full exams timed subtest by subtest like the real test.
Practice the other subtests
Or take the full free practice test: 30 questions from all 10 subtests, with a rough AFQT estimate at the end.
These are original practice questions; real ASVAB items are confidential. Practice scores are estimates, not official ASVAB scores. ASVAB Test is not affiliated with the U.S. Department of Defense or any military branch.