ASVAB General Science: What It Covers and How to Study

General Science (GS) is the ASVAB subtest that measures your basic knowledge of life science, earth and space science, and physical science. On the CAT-ASVAB you get 16 questions in 8 minutes, so you have about 30 seconds per question. General Science does not count toward your AFQT, the score that decides whether you can enlist, but it feeds several line scores that decide which military jobs you qualify for, so it matters for anyone aiming at a technical or medical field.

What does ASVAB General Science cover?

GS pulls from three broad areas of high school science. You are not expected to do lab-level work. The questions test whether you recognize core facts and how basic processes work.

The test rewards broad familiarity over deep expertise. Knowing a little about a lot beats knowing everything about one topic.

How is the General Science subtest formatted?

The format depends on which version you take. Nearly everyone tests on the computer version at MEPS now.

Both versions move fast. At roughly 30 seconds per question, you answer what you know quickly and make an educated guess on anything that stalls you, since there is no penalty for guessing.

What are the high-yield General Science facts to review?

Certain facts show up again and again. If you are short on time, memorize these first.

• Earth’s atmosphere is about 78 percent nitrogen and 21 percent oxygen.
• Arteries carry blood away from the heart; veins carry it back.
• The cell is the smallest unit of life that can function on its own.
• An atom has protons and neutrons in the nucleus and electrons orbiting it.
• Water is H2O; carbon dioxide is CO2.
• Universal blood donor is O negative; universal recipient is AB positive.
• Producers photosynthesize, consumers eat, decomposers break down organic matter.
• Taxonomy order: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

A quick memory aid for that last one is “Dear King Philip Come Over For Good Soup.”

What does a General Science question look like?

Here is a worked example in the style you will see.

Question. Which gas makes up approximately 78 percent of Earth’s atmosphere? The choices are oxygen, carbon dioxide, nitrogen, and argon.

Answer. Nitrogen. Earth’s atmosphere is roughly 78 percent nitrogen, 21 percent oxygen, about 0.9 percent argon, and a small fraction of carbon dioxide. The common mistake is choosing oxygen because it is the gas we breathe, but oxygen is the second most abundant, not the first. This is a recall question, so the fix is simply knowing the number.

Which jobs use your General Science score?

GS is a component of several Army line scores, which combine subtest results to set job eligibility. These subtests build the line scores even though they never touch your AFQT. [NOTE: verify current line score formulas before publishing]

Skilled Technical and Electronics fields, which include many medical, intelligence, and repair jobs, lean on GS. The other branches use their own composite systems with similar weighting. Ask your recruiter which line score your target job requires. [NOTE: verify branch-specific composites]

ASVABDRILL is an ASVAB practice test platform focused on AFQT improvement, built for military recruits, covering ASVAB, PiCAT, and verification-style practice.

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Related reading

• Complete ASVAB study guide for the full-test plan
• ASVAB line scores explained for how GS feeds job eligibility
• ASVAB mechanical comprehension guide
• ASVAB electronics information guide

Want to see where your science knowledge stands? Take a full-length ASVAB practice test and check your General Science section.