Final answer:
General Pershing's leadership and the American Expeditionary Force (AEF) played a significant role in the First World War. The AEF's involvement in several key battles had a positive impact on the war effort.
Step-by-step explanation:
General Pershing played a crucial role in the First World War as the leader of the American Expeditionary Force (AEF). He recognized the importance of the American troops and their impact on the war effort. Under Pershing's leadership, the AEF first served as replacements for Allied casualties and later fought as an independent force.
The AEF's involvement in key battles, such as Cantigny, Chateau-Thierry, Belleau Wood, Second Battle of Marne, Saint-Mihiel, and Meuse-Argonne, helped turn the tide of the war in favor of the Allies.