are the marines a branch of the navy
United States Marine Corps The United States Marine Corps (USMC), also known as the United States Marines, is a branch of the United States Armed Forces responsible for conducting amphibious operations[10] with the United States Navy. The U.S. Marine Corps is one of the four armed service branches in the U.S. Department of Defense (DoD) and one of the seven uniformed services of the United States.
Sergeant Major of the Marine Corps Sergeant Major of the Marine Corps (officially abbreviated to SMMC[1][2]) is a billet, as well as a unique enlisted grade of rank, with a unique non-commissioned grade of rank insignia, in the United States Marine Corps.