Final answer:
A US Marine Corps rifle squad consists of 13 Marines, including a squad leader and three fire teams each led by a team leader with additional roles such as automatic rifleman and assistant automatic rifleman.
Step-by-step explanation:
The size of a US Marine Corps rifle squad has changed over time, but as of the most recent standards, a rifle squad consists of 13 Marines. This structure includes a squad leader, typically a sergeant, who leads three fire teams, each led by a team leader, typically a corporal. Each fire team includes a team leader, an automatic rifleman, an assistant automatic rifleman, and a rifleman. The 13-member squad is a basic unit designed for effectiveness in various combat situations, balancing leadership, firepower, and maneuverability.