Final answer:
A joint force integrates multiple military branches under a single JFC, facilitating unified military operations and strategies by combining the strengths of services like the Army, Navy, Marine Corps, and Air Force.
Step-by-step explanation:
The force composed of significant elements assigned or attached to two or more military departments under a single Joint Force Commander (JFC) is known as a joint force.
This type of military organization allows for the integration and synchronization of multiple military branches, such as the Army, Navy, Marine Corps, and Air Force, to achieve a specific mission objective under unified command.
These joint forces are pivotal in multi-domain operations, enabling a comprehensive approach to military strategies and tactics. Coordinating such a vast array of diverse capabilities requires meticulous planning and a command structure that can leverage the unique strengths of each service.