Final answer:
A corporal in the Marine Corps wears a chevron as their rank insignia, which consists of two stripes pointing upwards with a cross at the bottom.
Step-by-step explanation:
The insignia worn by a corporal in the Marine Corps is a chevron. Specifically, a corporal wears two stripes or chevrons pointing upwards with a cross at the bottom. Unlike other military branches, the Marine Corps insignia for a corporal does not include devices like eagles or bars. The insignia represents the rank of the non-commissioned officer and is worn on the uniform as a symbol of authority and responsibility.