Final answer:
The purpose of the Close March movement is to close the interval between individuals of a squad in line to 4 inches, ensuring the unit moves as a compact and organized entity.
Step-by-step explanation:
The purpose of the Close March movement is to close the interval between individuals of a squad in line to 4 inches, which is option 1). This military command is essential to maintain order and discipline within a unit and is often utilized in various branches of the military, as seen in basic training scenarios like those in the Air Force. The close march enables a unit to move as a single, compact entity, enhancing its maneuverability and supportive strength. It is achieved through rigorous training where soldiers are taught to march in correct formations, maintain uniform appearance, and follow structured schedules, all of which contribute to a cohesive military presence.