Final answer:
The US entry into World War I benefitted the Allies by providing manpower, economic support, and shifting the balance of power.
Step-by-step explanation:
The Allies immediately benefitted from the US entering World War I in several ways. Firstly, the US brought a significant increase in manpower to the Allies' forces, strengthening their overall military power. Additionally, the US also provided economic support to the Allies through loans and supplies, which helped sustain their war effort. Finally, the US entry into the war shifted the balance of power in favor of the Allies, as it weakened the Central Powers' position and eventually led to their defeat.
Learn more about US entry into World War I