Which of the following branches is the largest and oldest of the military?

The Army is recognized as the largest and oldest branch of the U.S. military. Its origins can be traced back to the Continental Army, established in 1775 during the American Revolutionary War. As the primary land warfare force, the Army is responsible for defeating any land-based threats and securing large areas, which has made it a crucial component of national defense.

Throughout its history, the Army has undergone significant transformations and expansions to adapt to changing warfare tactics and technology. It plays a critical role in ground operations and has the largest number of active duty and reserve personnel compared to the other branches mentioned. This extensive history and the wide range of roles performed from conventional warfare to peacekeeping missions underscore its significance and size relative to the Navy, Air Force, and Marine Corps.