Which component is NOT part of the Army's structure according to Title 10 USC?

The Marine Corps Reserve is not a component of the Army's structure according to Title 10 of the United States Code (USC). Title 10 outlines the roles and organization of the armed forces, specifically detailing the structure and composition of the Army, which includes the Active Army, Army Reserve, and Army National Guard. Each of these components plays a distinct role within the Army, contributing to its overall mission and capabilities.

In contrast, the Marine Corps Reserve pertains to the United States Marine Corps and is not associated with the Army's organizational structure. This distinction is crucial to understanding the branches of the U.S. military and their respective reserves, as each service branch operates under different regulations and is governed by separate entities within the Department of Defense. Recognizing which components belong to the Army helps clarify the overall military structure as defined in Title 10 USC.