General Science ASVAB: What It Tests, Plus Practice
General Science tests your knowledge of physical and biological sciences at a broad, general level, not deep expertise in any single subject. It’s the first subtest administered on both CAT-ASVAB and paper, and it doesn’t touch your AFQT, but it’s one of four subtests in the Air Force’s Electronics composite, which makes it more consequential than its “doesn’t count toward enlistment” status might suggest.
(ASVAB HQ is not affiliated with, endorsed by, or administered by the Department of Defense, officialasvab.com, or any branch of the U.S. Armed Forces. All practice questions below are original, written by ASVAB HQ, not reproductions of real ASVAB test items.)
Because it’s administered first, some test-takers underestimate how much ground it covers, biology, chemistry, physics, earth science, all mixed together in a single short subtest, and end up caught off guard by a question outside whatever one subject they focused their review on.
What does General Science actually test?
A mix of basic biology (human body systems, cell structure, ecology), basic chemistry (elements, states of matter, simple reactions), basic physics (motion, energy, simple machines at a conceptual level), and earth/space science (weather, the solar system, geology basics). Nothing at an advanced or specialized level; questions stay at a general high-school-survey-course depth across all these areas rather than testing deep knowledge of any one.
| Format | Questions | Time limit |
|---|---|---|
| CAT-ASVAB | 15 scored | 12 min |
| Paper-and-pencil | 25 | 11 min |
Source: officialasvab.com, “What to Expect When You Take the ASVAB,” accessed 2026-07-18.
Practice questions (original, written by ASVAB HQ)
1. Which organ is primarily responsible for filtering waste products out of the blood? A) Liver B) Kidney C) Pancreas D) Spleen
Answer: B) Kidney. The kidneys filter waste and excess fluid from the blood to produce urine.
2. Which of the following is a chemical change, rather than a physical change? A) Melting ice B) Tearing paper C) Rusting iron D) Dissolving sugar in water
Answer: C) Rusting iron. Rusting is a chemical reaction between iron and oxygen that forms a new substance (iron oxide). The other three options change the form of a substance without altering its chemical composition.
3. What force is primarily responsible for keeping planets in orbit around the sun? A) Magnetism B) Gravity C) Friction D) Air pressure
Answer: B) Gravity. Gravitational attraction between the sun and each planet keeps the planets in their orbits.
4. Which blood type is considered the universal donor? A) Type A B) Type B C) Type AB D) Type O negative
Answer: D) Type O negative. Type O negative blood lacks the A, B, and Rh antigens that trigger immune reactions in most recipients, making it broadly compatible.
5. What is the primary function of the Earth’s ozone layer? A) Producing oxygen for the atmosphere B) Absorbing most of the sun’s ultraviolet radiation C) Regulating ocean tides D) Trapping heat to warm the planet’s surface
Answer: B) Absorbing most of the sun’s ultraviolet radiation. The ozone layer, located in the stratosphere, absorbs the majority of incoming UV radiation before it reaches the surface, distinct from the greenhouse gases that trap heat.
Why does this subtest feel unpredictable to study for?
Because “science” isn’t one subject on this test; it’s four loosely related subjects compressed into 11 to 12 minutes. A study plan built around only biology, or only physics, will leave real gaps. The fix is breadth over depth: a solid working knowledge of basic concepts across biology, chemistry, physics, and earth science beats deep expertise in just one of them, since the subtest samples from all four roughly evenly rather than concentrating on any single area.
A practical way to structure review is to spend one focused session per sub-area rather than one long, unfocused “science” study block. Cover the human body’s major systems and basic ecology in one session, states of matter and simple reactions in another, motion and simple machines in a third, and the solar system and weather basics in a fourth. Treating each sub-area as its own small unit, rather than one undifferentiated blob called “science,” makes gaps easier to spot and close.
Why does the Air Force weight this subtest so specifically?
Because General Science is one of the four subtests in the Air Force’s published Electronics composite (AR + EI + GS + MK), alongside Arithmetic Reasoning, Electronics Information, and Math Knowledge. That composite gates a range of Air Force technical jobs, so someone targeting an electronics-heavy AFSC benefits from treating General Science as a real study priority even though it has zero effect on their AFQT. See our Air Force score requirements breakdown for the full composite.
Run the free ASVAB HQ practice quiz to check your General Science standard score across all four sub-areas before test day.
FAQ
Does General Science affect my AFQT? No. It’s one of the six subtests that don’t feed the AFQT. It matters for line-score composites, including the Air Force’s Electronics composite, not enlistment eligibility.
Do I need a science background to do well on General Science? Not a specialized one. The subtest tests broad, general-level knowledge across biology, chemistry, physics, and earth science rather than advanced or specialized content in any single field.
How many General Science questions are on the ASVAB? 15 scored on CAT-ASVAB, 25 on the paper-and-pencil version.
Is General Science the easiest subtest? It’s often perceived that way because the content is general rather than technical, but its breadth across four unrelated subject areas can catch unprepared test-takers off guard just as easily as a narrower, harder-seeming subtest.
Which branches use General Science for job qualification? The Air Force’s Electronics composite is the clearest documented example. Other branches likely weigh General Science in some of their own technical composites, though this article only cites the specific formula we could verify.
Should I study General Science if I don’t want a technical job? It’s worth at least a baseline review, since a low General Science score is one of the six subtests that can otherwise sit neglected purely because it doesn’t touch your AFQT. Even for non-technical jobs, a well-rounded subtest profile can matter if your job preferences change once you’re actually enlisted.
Are General Science questions ever illustrated with diagrams? Generally no. Unlike Mechanical Comprehension, which frequently uses diagrams of levers and gears, General Science questions are typically text-based, testing recall and basic conceptual understanding rather than reading a visual.
Bottom line: General Science samples broadly across biology, chemistry, physics, and earth science rather than testing any one deeply, doesn’t touch your AFQT, but directly builds the Air Force’s Electronics composite, so treat breadth of review, not depth in one subject, as the actual study strategy here.