Word Knowledge (WK), Paragraph Comprehension (PC), Arithmetic Reasoning (AR), and Mathematics Knowledge (MK). Scores on the AFQT are used to determine your eligibility for enlistment in the Army, Navy, Air Force, or Marine Corps. The other six test scores on the ASVAB tests are used to determine the best job for you in the military as your grades will demonstrate knowledge, skill, and interest in certain subjects and tasks. 
The General Science section of the test covers earth, space, and physical and life sciences. Because science is such a vast and dynamic topic, focus your study on basic principles. This gives you a good foundation to work through any question that is asked of you. Typical questions may include: “Why is air less dense than water?” or “How do you convert Celsius temperature to Fahrenheit?” The CAT-ASVAB test asks 16 questions in 8 minutes, while the pencil-and-paper version asks 25 questions in 11 minutes.
After adopting the test in 1976 the test became a way of indicating whether or not an individual was 100% qualified to serve. As previously mentioned this aptitude test has a colorful history. That is because it underwent a dramatic change in 2002 and another dramatic change in 2004. The change that occurred in 2002 expanded the categories of the test and the overall difficulty. This can be seen by the addition of all of the diverse categories below: