About General Science

The General Science section evaluates your understanding of fundamental scientific concepts across multiple disciplines. This includes life science (biology, ecology, human anatomy), physical science (chemistry, physics), and earth and space science (geology, meteorology, astronomy). On the CAT-ASVAB, you will have 15 scored questions with a 12-minute official subtest limit. While this section does not directly contribute to your AFQT score, it is a critical component of several composite line scores including ST (Skilled Technical), EL (Electronics), and GM (General Maintenance), which determine eligibility for many technical military jobs.

Topics Covered

Human Biology & Anatomy
Cell Biology & Genetics
Ecology & Ecosystems
Chemistry Fundamentals
Physics Basics
Earth Science & Geology
Weather & Meteorology
Astronomy & Space Science
Scientific Method
Nutrition & Health

Sample Questions

Sample Question 1
What is Avogadro's number approximately?
  • 3.14 × 10²³
  • 6.02 × 10²³
  • 1.6 × 10⁻¹⁹
  • 9.8 × 10²⁰
Avogadro's number is approximately 6.02 × 10²³, the number of particles in a mole.
Sample Question 2
What layer of the atmosphere contains the ozone layer?
  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
The ozone layer is located in the stratosphere, about 15-35 km above Earth's surface.
Sample Question 3
What is the half-life of a radioactive substance?
  • Time to fully decay
  • Time for half the atoms to decay
  • Half its weight
  • Half its volume
Half-life is the time required for half of the radioactive atoms to decay.

Study Tips for General Science

Focus on Breadth, Not Depth

The GS section covers many topics at a surface level. Focus on understanding key concepts across all sciences rather than deep-diving into one area.

Use Flashcards for Terminology

Many GS questions test vocabulary and definitions. Create flashcards for scientific terms, especially in biology and chemistry.

Review the Periodic Table Basics

Know the common elements, their symbols, and basic properties. You don't need to memorize the entire table, but understanding groups and periods helps.