[DesertRhino]

No, the navy does not “have its own land force, the Marines”. The Marines are separate and answer only to marine officers up to the joint Chiefs of staff. The commandant answers to the civilian Secretary of the Navy.
Marine units are not under the command of navy officers, except for joint commands.

By that standard, Navy forces are sometimes under the command of USAF or USA officers.

[quadrant]

The Navy and the Marine Corps are a team; and as with all teams frictions develop among members from time-to-time; but in the end the Navy and the Marines are still on the same team. Both need each other.

[Hulka]

Indeed.

The Navy is QRF, powerful and fast, but when it comes to heavy sustained operations, need Air Force or Army.