Final answer:
In World War I, U.S. soldiers were nicknamed Doughboys, part of the AEF. Rough Riders and Harlem Hellfighters were other notable military groups.
Explanation:
The nickname for U.S. soldiers in World War I was Doughboys. During this time, they were part of the American Expeditionary Force (AEF) led by General John J. Pershing and served as replacements for Allied casualties in World War I.
Another group, the Rough Riders, was founded by Theodore Roosevelt and fought in the Spanish American War. The Harlem Hellfighters, known for their valor, were members of the 369th US Infantry who fought with the French army.
Learn more about World War I here:
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