Question

what was the impact of the u.s. decision to enter world war i?
the size and enthusiasm of the american forces bolstered the french and british.
with american help the russians were able to successfully take on the germans.
the germans were overwhelmed and decided to surrender.
the american entry into the war brought very few changes.

Explanation:

When the U.S. entered World War I, its large - scale and enthusiastic forces provided significant support to the French and British. The Russians withdrew from the war due to internal revolution (Bolshevik Revolution) rather than being able to "successfully take on the Germans" with U.S. help. The Germans did not immediately surrender upon U.S. entry; the war continued for some time after. And the U.S. entry had a major impact, not "very few changes".

Answer:

The size and enthusiasm of the American forces bolstered the French and British.