Final answer:
The Secretary of Defense and the Chairman of the Joint Chiefs of Staff oversee the process of assigning and allocating forces to combatant commanders.
Step-by-step explanation:
The process of assigning forces to combatant commanders and allocating additional forces in the event of contingency operations is the responsibility of the Secretary of Defense and the Chairman of the Joint Chiefs of Staff.
The Secretary of Defense is the civilian head of the U.S. Department of Defense and oversees all elements of the U.S. armed forces, including the Army, Navy, Marine Corps, and Air Force. They work closely with the Chairman of the Joint Chiefs of Staff, who is the highest-ranking military officer and principal military advisor to the President and the Secretary of Defense.
Together, the Secretary of Defense and the Chairman of the Joint Chiefs of Staff follow a process that involves assessing the needs of combatant commanders, determining the available forces, and making strategic decisions to assign and allocate those forces to meet mission requirements.