In the Army enlisted ranks are Private, Corporal/Specialist and Sargent (there are multiple levels of Private and Sargent) . Corporal and Sargent are considered Non-Commissioned Officers (NCOs). Specialists are not above PFC but move up based technical knowledge rather than leadership responsibilities. NCOs fill most of the leadership rolls in the Army. Commissioned officers receive a commission and usually need college degrees to enter or advance. Officer ranks are Lieutenant, Captain, Major, Colonel, and General. All commissioned officers outrank all enlisted soldiers. Though experienced sergeants are often more knowledgeable and effective then fresh second lieutenants. Warrant officers receive a warrant rather than a commission and rank between enlisted soldiers and commissioned officers. Warrant officers have highly specialized knowledge and skills and are relied on for the technical expertise though Warrant officers can also be in positions of leadership. Even though Warrant officers are below all Commissioned Officers in rank,high ranking Warrant Officers generally receive more pay than low ranking COs.
Well, a particular rank doesn't specify a particular job, but rather a "chain of command". For example, you are a seargent and I'm a private, we are both doing the same job let's say in radar or communications. If a major decision has to be made and you and I are the only ones on duty, then you are responsible for that decision because you out rank me, if a colonel were present, then he or she would be responsible because they out rank you and me. Another example is in combat : Everyone of all different ranks are fighting together the same battle, but the higher the rank the more responsibility. Someone has to be "in charge" which is typically an Officer or non-commissioned officer.
each rank in the army gives a different command and without it there would be no leadership. you need these ranks to keep order
each rank pays more money the the perverse rank
Orchestrate the destruction of other armies.