Final answer:
The number of ribbons a male Marine can wear in one row is generally up to four, depending on the chest size and ribbon size, with multiple rows organized in a pyramid fashion.
Step-by-step explanation:
In the United States Marine Corps, ribbon bars are used to denote awards and are worn in rows on the left chest of the uniform. The number of ribbons that can be worn in a row depends on the size of the Marine's chest and the regulation size of the ribbons being used. However, a standard rule is that ribbons should be arranged in rows that cover as much of the ribbons as possible without overlapping, and typically, up to four ribbons can be worn side by side in one row. If the amount of ribbons exceeds four, they must be arranged in multiple rows with the top rows having fewer ribbons to maintain a pyramid appearance.
This is in accordance with U.S. Marine Corps regulations and is to ensure a neat and professional appearance.