Commander-in-chief: President of the United States Secretary of Defense Deputy Secretary of Defense Secretary of Homeland Security Deputy Secretary of Homeland Security Joint Chiefs of Staff: Chairman Vice Chairman United States Congress: Committees on Armed Services: Senate House Active duty four-star officers United States military seniority National Security Act of 1947 Goldwater–Nichols Act
The President, Secretary of Defense and other senior executive officials are advised by a seven-member Joint Chiefs of Staff, which is headed by the Chairman of the Joint Chiefs of Staff, the highest-ranking officer in the United States military and the Vice Chairman of the Joint Chiefs of Staff.[20] The rest of the body is composed of the heads of each of the DoD's service branches (the Chief of Staff of the Army, the Chief of Naval Operations, the Commandant of the Marine Corps and the Chief of Staff of the Air Force) as well as the Chief of the National Guard Bureau. Although commanding one of the five military branches, the Commandant of the Coast Guard is not a member of the Joint Chiefs of Staff. Despite being composed of the highest-ranking officers in each of the respective branches, the Joint Chiefs of Staff does not possess operational command authority. Rather, the Goldwater-Nichols Act charges them only with advisory power.[21]
These are sections, or sub-tests, in the ASVAB:  Word Knowledge (WK), Paragraph Comprehension (PC), Arithmetic Reasoning (AR), Mathematics Knowledge (MK), General Science (GS), Mechanical Comprehension (MC), Electronics Information (EI), and Assembling Objects (AO), Auto & Shop Information (AS):  * AI and SI are administered as separate tests in the CAT-ASVAB (computerized version), but combined into one single score (labeled AS).

A military or an armed force is a professional organization formally authorized by a sovereign state to use lethal or deadly force and weapons to support the interests of the state. It typically consists of branches such as an Army, Navy, Air Force, and in certain countries the Marines and Coast Guard. The task of the military is usually defined as defense of the state, and its citizens, and the prosecution of war against another state. The military may also have additional sanctioned and non-sanctioned functions within a society, including, the promotion of a political agenda, protecting corporate economic interests, internal population control, construction, emergency services, social ceremonies, and guarding important areas. The military may also function as a discrete subculture within a larger civil society, through the development of separate infrastructures, which may include housing, schools, utilities, logistics, health and medical, law, food production, finance and banking.

The Arithmetic Reasoning section of the test measures your ability to solve arithmetic word problems. You may be asked questions such as “If the tire of a car rotates at a constant speed of 552 times in 1 minute, how many times will the tire rotate in half an hour?” Therefore, reviewing common math key words associated with each operation is recommended. For example, if you see the key words “in all,” the problem deals with addition. If the problem asks you to “find the difference,” you are being asked to subtract. If a question asks “how many times” per day or week, you know you are dealing with multiplication. If it asks “how many in each,” you should be thinking about division. The CAT-ASVAB has 16 questions in 39 minutes; the paper-and-pencil version has 30 questions in 36 minutes.

You can take the test as a junior or senior in high school and use the score to enlist, provided that you are at least 17 years old and took the test no earlier than 2 years before you begin enlistment processing. If you are at least 17, you can take the test at a Military Processing Station (MEP) or a satellite Military Entrance Test (MET) location.
One ASVAB sub-measure, the Armed Forces Qualification Test (AFQT)--which is just a separate analysis of the same tests that focuses only on four of the subtests--is also population-referenced, but its score from 1-99 is a percentile score. This means that if you score a 73, you scored as well as or higher than 73% of test-takers in the national sample.