Depends. Only the US Army, Marine Corps, and the US Coast Guard accept the ASVAB for officer applicants. Prospective officer candidates looking at the Air Force and the Navy do not have to take the ASVAB. Instead prospective USAF and USN officer candidates will take the AFOQT and the ASTB-E. If you are interested in joining the US Coast Guard as an officer, you also have the option of taking the Navy's officer candidate test, the ASTB-E, in lieu of the ASVAB.
Law prohibits applicants in Category V from enlisting.[6] In addition, there are constraints placed on Category IV recruits; recruits in Category IV must be high school diploma graduates but cannot be denied enlistment solely on this criteria if the recruit is needed to satisfy established strength requirements. Furthermore, the law constrains the percentage of accessions who can fall between Categories IV-V (currently, the limit is 20% of all persons originally enlisted in a given armed force in a given fiscal year).[6]
The ASVAB test is taken by individuals interested in joining the U.S. military. It may be taken by high school students in the 10th, 11th or 12th grade. Or, it may be taken by someone who has earned a GED or higher degree. Along with determining your suitability for enlistment, the score you receive on this test lets officials know what military occupational specialties you may qualify for. 
Arithmetic reasoning refers to the process of solving math word problems – you know those questions you had in elementary, middle and high school that might involve two trains traveling at different speeds or determining how many different pieces of fruit Tommy brought home from the grocery store. Whether you enjoy these types of problems or dread them, there is a process you can use to make solving them quicker and easier. Your test administrator will provide you with scratch paper and a number two pencil for this portion of the ASVAB. Calculators are not allowed. If you are taking the pencil-and-paper test, you will 36 minutes to answer 30 questions and if you are taking the computer version, you will have 39 minutes to answer 16 questions.
The General Science subtest of the Armed Services Vocational Aptitude Battery measures your knowledge of a variety of sciences, including: Earth science, biology, chemistry, health and more. The General Science subtest is NOT part of your Armed Forces Qualification Test score. However, it used to help determine qualification for a number of different military jobs. On this subtest, you will 25 questions to answer in 11 minutes on the paper version of the ASVAB and you will have 16 questions to answer in 8 minutes on the CAT-ASVAB.
Ecology is the study of interactions between organisms and their environment. Regions that share a similar climate and soil type (and, therefore, similar animal and plant life) are called biomes and house a community of species that each belong to a population.  This combination of biome and community make up an ecosystem that consists of predators that utilize other living organisms as food, prey that becomes food to predators, and parasites that lives in or on another organism and takes nutrients from its host.
25. Use the following passage to answer questions 25 and 26. Sarah is about to fly from New York to Los Angeles. She packs the night before and checks her list three times. Anxiety keeps her from sleeping well. The next morning, she accidentally puts salt in her coffee instead of sugar. She forgets her purse and has to go back to the house to get it. Finally, she arrives at the airport just in time to catch her flight. The flight is uneventful, and soon Sarah is landing at LAX. Her sister is waiting for her. What was the main idea of this passage?
The sections are as follows: General Science-25 questions of life, earth, and physical sciences. Arithmetic Reasoning-30 questions involving basic math. Word Knowledge-35 questions on vocabulary and synonyms. Paragraph Comprehension-15 questions testing your reading and comprehension skills. Mathematics Knowledge-25 questions on math concepts and how to use them. Electronics Information-20 questions on basic electronic principles. Auto and Shop Information-25 questions about cars, both maintaining and repairing them, and working with wood and metal. Mechanical Comprehension-25 questions on the properties of different materials, and mechanical principles.
The SAT requires training of the mind. More specifically it requires one to be able to pick up on context clues, make valid assumptions, and express concrete facts. This is why millions of students study intensely before they jump right into the test. Imagine if another area was added onto that same test. The person studying for that test would then need to study even harder. That is the logic that should be put forth when preparing for the ASVAB. It requires that a person expresses the previously mentioned skills while adding the verbal/physical aspects. The question becomes “How does one prepare themselves for this rigorous test?”