Final answer:
A modern rifle fire team usually consists of four personnel, though historical examples like Roman Legion squads show different numbers. The My Lai Massacre is an instance where larger military units were involved in an operation.
Step-by-step explanation:
The size of a rifle fire team can vary depending on the military organization and historical period. However, in modern military structures, particularly in the U.S. Army, Marine Corps, and similar forces, a standard rifle fire team typically consists of four personnel. Each member has a specific role and together they form a cohesive unit capable of performing a wide range of infantry tasks. Historical examples also show variations in team sizes. For instance, in the Roman Legion, a squad (or "tentmates") comprised of 8 soldiers was the smallest unit, which differs slightly from current fire team structures. Additionally, historical events such as the My Lai Massacre involved larger units demonstrating the varying scales of military operations through history.