Militaries often function as societies within societies, by having their own military communities, economies, education, medicine, and other aspects of a functioning civilian society. Although a 'military' is not limited to nations in of itself as many private military companies (or PMC's) can be used or 'hired' by organisations and figures as security, escort, or other means of protection; where police, agencies, or militaries are absent or not trusted.
Military history has a number of facets. One main facet is to learn from past accomplishments and mistakes, so as to more effectively wage war in the future. Another is to create a sense of military tradition, which is used to create cohesive military forces. Still, another may be to learn to prevent wars more effectively. Human knowledge about the military is largely based on both recorded and oral history of military conflicts (war), their participating armies and navies and, more recently, air forces.
Each service has a uniformed head who is considered the highest-ranking officer within their respective service, with the exception of the chairman and vice chairman of the Joint Chiefs of Staff, and the chief of the National Guard Bureau. They are responsible for ensuring personnel readiness, policy, planning and training and equipping their respective military services for the combatant commanders to utilize. They also serve as senior military advisors to the President, the Secretary of Defense, their respective service secretaries, as well as other councils they may be called to serve on. They are as follows:
Sergeant Leigh Ann Hester became the first woman to receive the Silver Star, the third-highest U.S. decoration for valor, for direct participation in combat. In Afghanistan, Monica Lin Brown was presented the Silver Star for shielding wounded soldiers with her body. In March 2012, the U.S. military had two women, Ann E. Dunwoody and Janet C. Wolfenbarger, with the rank of four-star general. In 2016, Air Force General Lori Robinson became the first female officer to command a major Unified Combatant Command (USNORTHCOM) in the history of the United States Armed Forces.
The meaning of military tactics has changed over time; from the deployment and manoeuvring of entire land armies on the fields of ancient battles, and galley fleets; to modern use of small unit ambushes, encirclements, bombardment attacks, frontal assaults, air assaults, hit-and-run tactics used mainly by guerrilla forces, and, in some cases, suicide attacks on land and at sea. Evolution of aerial warfare introduced its own air combat tactics. Often, military deception, in the form of military camouflage or misdirection using decoys, is used to confuse the enemy as a tactic.
Under current Department of Defense regulation, the various components of the U.S. Armed Forces have a set order of seniority. Examples of the use of this system include the display of service flags, placement of Soldiers, Marines, Sailors, Airmen and Coast Guardsmen in formation, etc. When the Coast Guard shall operate as part of the Department of the Navy, United States Coast Guard Academy cadets, the United States Coast Guard and the Coast Guard Reserve shall take precedence after United States Naval Academy midshipmen; the United States Navy; and Navy Reserve, respectively.
The AFQT (Armed Forces Qualifying Test) score is arguably the most important ASVAB score because it determines whether you’re eligible to join the military branch of your choice. Although the AFQT is often called the “overall ASVAB score,” that’s not quite correct, because it’s derived from only four subtests: Verbal Expression (VE), which is computed from the Paragraph Comprehension (PC) and Word Knowledge (WK) subtests, Arithmetic Reasoning (AR), and Math Knowledge (MK).