ASVAB General Science Practice Test
Updated October 27, 2026
General Science (GS) has 15 scored questions on the CAT-ASVAB. It covers basic life science, physical science (chemistry and physics) and Earth and space science, at about a high school level. It doesn’t count toward your AFQT, but it’s part of the line scores for many technical and medical military jobs. Try the free questions below.
What General Science covers
- Life science: cells, the human body, nutrition, genetics and ecology
- Physical science: matter, the periodic table, chemical reactions, energy, force and motion
- Earth and space science: weather, geology, the atmosphere and the solar system
Free General Science practice questions
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Which blood cells help the body fight infection?Answer: CWhite blood cells defend the body against infection. Red blood cells carry oxygen, and platelets help blood clot.
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What is the chemical symbol for sodium?Answer: DSodium's symbol is Na, from its Latin name, natrium.
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Which planet is closest to the Sun?Answer: AMercury is the closest planet to the Sun.
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Water freezes at what temperature on the Celsius scale?Answer: BWater freezes at 0°C (32°F) and boils at 100°C (212°F) at sea level.
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Which layer of the atmosphere is closest to Earth's surface, where weather occurs?Answer: DThe troposphere is the lowest layer, where nearly all weather happens. The ozone layer is in the stratosphere above it.
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A force of 20 newtons pushes a 4-kilogram object. What is its acceleration? (F = ma)Answer: Ba = F ÷ m = 20 ÷ 4 = 5 m/s².
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Which organ produces insulin?Answer: CThe pancreas makes insulin, which helps cells take in glucose from the blood.
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What is the powerhouse of the cell, where most energy is produced?Answer: BMitochondria carry out cellular respiration and produce most of the cell's energy (ATP).
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Which vitamin does the body make when skin is exposed to sunlight?Answer: CSkin produces vitamin D when exposed to ultraviolet light from the sun.
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What is the most abundant gas in Earth's atmosphere?Answer: DNitrogen makes up about 78% of the atmosphere. Oxygen is about 21%.
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What is the speed of sound compared with the speed of light?Answer: ALight travels far faster than sound, which is why you see lightning before you hear thunder.
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Which type of rock forms from cooled magma or lava?Answer: BIgneous rock forms when molten rock cools and hardens. Sedimentary rock forms from compacted sediment, and metamorphic rock from heat and pressure.
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What is the chemical formula for water?Answer: CWater is two hydrogen atoms bonded to one oxygen atom: H₂O. NaCl is table salt.
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Which part of the human body pumps blood?Answer: DThe heart pumps blood through the circulatory system.
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A solution with a pH of 9 is:Answer: AA pH above 7 is basic, 7 is neutral, and below 7 is acidic.
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Which planet is known as the Red Planet?Answer: BMars looks red because of iron oxide (rust) on its surface.
See also Mechanical Comprehension and Electronics Information.
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