General Science (GS)
General Science (GS) is a broad, high-school-level science subtest covering life, earth and space, and physical science. It isn't part of the AFQT, but it feeds line scores for many technical and medical jobs.
Practise General Science freeAlready know what's on it and still stuck? How to improve your General Science score.
Life science (the biggest share)
Cell parts and their jobs (mitochondria make ATP; the nucleus holds DNA; chloroplasts do photosynthesis); photosynthesis vs. cellular respiration; genetics (DNA, genes, dominant vs. recessive, 46 chromosomes); the human body systems (circulatory, respiratory, digestive, nervous, skeletal); and ecology (food chains, producers/consumers, herbivore/carnivore/omnivore).
Earth & space science
Earth's layers (crust, mantle, core), the rock cycle (igneous, sedimentary, metamorphic) and plate tectonics; the water cycle and basic weather; and astronomy (the order of the planets, the Sun as a star, why the Moon has phases, day/night from Earth's rotation).
Physical science
Physics: Newton's laws in plain terms, work = force × distance, forms of energy, waves, and the basics of electricity and magnetism (like poles repel). Chemistry: atomic structure (protons, neutrons, electrons), reading the periodic table (atomic number = protons), states of matter, and the pH scale (below 7 acidic, 7 neutral, above 7 basic).
Test-day strategy
It's breadth, not depth — know a little about a lot. Prioritise biology and earth science, which appear most. Flashcards work well here. Learn metric units and prefixes.
Key takeaways
- Not an AFQT subtest, but it feeds many technical/medical line scores.
- Life science is the largest chunk — start there.
- Recall-heavy: flashcards and quick facts beat deep study.
Start a free General Science practice set — timed, with a worked explanation after every question.
Go to General Science practiceFree sample General Science questions
A few sample questions with worked answers. Our free General Science practice set has 198 questions in total — every one with a full explanation.
- A.Helium
- B.Oxygen ✓
- C.Nitrogen
- D.Carbon dioxide
- A.it moves more quickly
- B.its molecules are closer together
- C.it is lighter by nature
- D.its molecules are farther apart ✓
- A.created from nothing at all
- B.conserved, never lost ✓
- C.completely destroyed away
- D.always exactly doubled
- A.30 km/s
- B.300,000 km/s ✓
- C.3,000 m/s
- D.300 m/s
- A.44
- B.92
- C.23
- D.46 ✓
General Science cheat sheet
The formulas and facts worth memorising for this subtest. See all ASVAB cheat sheets →
- Mitochondria = energy (ATP) · nucleus = DNA · chloroplast = photosynthesis · ribosome = proteins
- Photosynthesis: CO₂ + water + light → sugar + O₂; respiration is the reverse
- Humans: 206 bones, 46 chromosomes (23 pairs), heart has 4 chambers
- Earth layers: crust, mantle, core; rocks: igneous, sedimentary, metamorphic
- Planet order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
- Atom: protons (+), neutrons (0), electrons (−); atomic number = number of protons
- pH < 7 acidic, 7 neutral, > 7 basic
- Water freezes 0°C/32°F, boils 100°C/212°F; F = 1.8 × C + 32
- Work = force × distance; speed of light ≈ 3 × 10^8 m/s