Basically, the Army concentrates on providing ground forces for the United States military, while the Navy is tasked with fighting across the seas.
The Army is the oldest and largest branch of the United States military. Its ground troops are supported by the Army's own helicopters, tanks, artillery, and tactical nuclear weapons during warfare.The Army has two Reserve units, the Army Reserves and the Army National Guard. Each state has its own National Guard, while the Army Reserves fall under the jurisdiction of the federal government. Both the President and the Secretary of Defense may call up Reserve troops for federal service in times of need. The Army is commanded by a four star general, the Army Chief of Staff, who answers to the Secretary of the Army.
The Navy's supremacy rests on its military prowess across the seafront. Naval troops are supported by the Navy's own submarines and aircraft carriers. The Navy often supports air missions by the Air Force. Many aircraft naval carriers are often equipped with cruise missiles. In times of need, the Navy may call up its Naval Reserves for support. However, a major difference between the Army and the Navy is that the Navy has no Naval National Guards. The Navy is commanded by a four star admiral, the Chief of Naval Operations, who answers to the Secretary of the Navy.
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