Final answer:
The Individual and Medical Readiness of the U.S. Navy and Marine Corps is governed by policies set by Congress and executed by the President as Commander in Chief, with support from various government departments and historic health services.
Step-by-step explanation:
The policies and procedures that ensure the Individual and Medical Readiness of Navy and Marine Corps Active and Reserve component Service Members are established by various legislative and executive authorities. The Constitution grants Congress the power 'To provide and maintain a Navy; To make Rules for the Government and Regulation of the land and naval Forces;' which encompasses the authority to set requirements for medical readiness. Additionally, the President, as the Commander in Chief of the military, plays a crucial role in overseeing the execution of these policies. This framework is supported by various departments and organizations within the government, such as the Department of Veterans Affairs, which oversees health care services for U.S. veterans, and historical entities like the Marine Hospital Service, an early form of medical care for seamen that evolved into today's U.S. Public Health Service.