The ASVAB test can be taken at your school or a MEPS (Military Entrance Processing Stations) or MET (Mobile Examination Test) sites.  When the ASVAB is administered at your school, it is usually part of the Student Testing Program or Career Exploration Program.  When the ASVAB is given at MEPS or MET sites, it is part of the Enlistment Testing Program.  The ASVAB test content is the same no matter where you take it, except that you will not have to take the Assembling Objects test if you take the test at your school (as part of the Student Testing Program).  When you take the test in the Student Testing Program you will receive three composite scores (Verbal Skills, Math Skills, and Science and Technical Skills).  When you take the ASVAB as part of the Enlistment Testing Program, you will receive an AFQT (Armed Forces Qualification Test) score and Service composite scores.  These scores are used for assigning your military job.
General Science tests the ability to answer questions on a variety of science topics drawn from courses taught in most high schools. The life science items cover botany, zoology, anatomy and physiology, and ecology. The earth and space science items are based on astronomy, geology, meteorology and oceanography. The physical science items measure force and motion mechanics, energy, fluids, atomic structure and chemistry.

I thought I was just buying an extra book, that I would most likely not put attention to. But, it was not. This book is filled with practice questions, which I got to study before hand thanks to the "2015 / 2016 ASVAB For Dummies". These two books makes a great combination. One to study and the other to test how far you have improved by testing yourself. I am glad I bought it. I recommend it to everyone who is thinking of taking the ASVAB or the AFQT. Just have in mind, that this book is all about questions, of course it will give you the correct answer in the back of it, but it will not go into detail as much as the "2015 / 2016 ASVAB For Dummies" book.

From the time of its inception, the U.S. Armed Forces played a decisive role in the history of the United States. A sense of national unity and identity was forged as a result of victory in the First Barbary War and the Second Barbary War. Even so, the founders of the United States were suspicious of a permanent military force. It played a critical role in the American Civil War, continuing to serve as the armed forces of the United States, although a number of its officers resigned to join the military of the Confederate States. The National Security Act of 1947, adopted following World War II and during the Cold War's onset, created the modern U.S. military framework. The Act established the National Military Establishment, headed by the Secretary of Defense; and created the Department of the Air Force and the National Security Council. It was amended in 1949, renaming the National Military Establishment the Department of Defense, and merged the cabinet-level Department of the Army, Department of the Navy, and Department of the Air Force, into the Department of Defense.
The Armed Forces Qualifying Test, commonly known as the AFQT, is used by the United States military to assess prospective service members. The questions on this test are taken from the Armed Forces Vocational Aptitude Battery. The following ASVAB subject areas are included in the test: arithmetical reasoning (AR), mathematics knowledge (MK), verbal expression (VE), paragraph comprehension (PC), and word knowledge (WK). These are the most general academic content areas on the ASVAB. The formula for computing scores on the AFQT test is AR + MK + (2 x VE), with VE = PC + MK. Scores are then placed in the following categories: Category I (93 to 99), Category II (65 to 92), Category IIIA (50 to 64), Category IIIB (31 to 49), Category IVA (21 to 30), Category IVB (16 to 20), Category IVC (10 to 15), and Category V (0 to 9). These AFQT test score categories are percentiles, which indicate how well the test-taker performed relative to others. A person scoring a 50, for example, performed as well as or better than half of the other test-takers. The percentile score is based on the raw score (number of questions answered correctly) and the difficulty of the test version. The minimum passing score for the AFQT varies between branches of the military.
High school and postsecondary students can also take the ASVAB test as part of the Department of Defense’s Career Exploration Program. This paper-and-pencil version of the test is the same as the paper-and-pencil enlistment version but excludes the Assembling Objects section. It is intended to help those students considering a career in the military to discover their strengths in both military and civilian jobs. If the student scores high enough in the AFQT section of the test, he may use the score to enlist within the two-year expiration window.
Whereas recruits who join as officers tend to be upwardly-mobile,[14][15] most enlisted personnel have a childhood background of relative socio-economic deprivation.[16][17][18] For example, after the US suspended conscription in 1973, "the military disproportionately attracted African American men, men from lower-status socioeconomic backgrounds, men who had been in nonacademic high school programs, and men whose high school grades tended to be low".[14]
The Armed Services Vocational Aptitude Battery is more commonly known as the ASVAB Test. If you are interested in a military career, you will need to pass this challenging test in order to qualify. It is used for all branches of the military which includes the Army, Navy, Air Force, Marines, National Guard, and Coast Guard. It is also used to gauge your abilities in specific areas that may be relevant to your job assignments within the military. For more information about the exact details of this exam, check out our article titled What is the ASVAB Test?

Direct commission: civilians who have special skills that are critical to sustaining military operations and supporting troops may receive direct commissions. These officers occupy leadership positions in law, medicine, dentistry, pharmacy, intelligence, supply-logistics-transportation, engineering, public affairs, chaplain, oceanography and others.
High school students can take the test in their sophomore, junior, or senior years, although scores from sophomore tests can’t be used for enlistment purposes. There is no charge to sit for the exam, and the results will have no impact on your high school academic record or your college application. This is a risk-free way to better evaluate your opportunities for the future after high school graduation.
Test scores provide only one measure of your skills and abilities.  Test scores and grades, combined with information about your interests, values, skills, and achievements may help you select appropriate occupations for career exploration.  As you explore careers, you can compare your skills with the skill requirements of occupations in which you are interested.