I'm not sure i tried my best ;(
Answer:
The contributions of the United States military to the Allied effort were decisive. Since the Russians decided to quit the war, the Germans were able to move many of their troops from the eastern front to the stalemate in the West. The seemingly infinite supply of fresh American soldiers countered this potential advantage and was demoralizing to the Germans. American soldiers entered the bloody trenches and by November 1918, the war was over. Contributions to the war effort were not confined to the battlefield. The entire American economy was mobilized to win the war. From planting extra vegetables to keeping the furnace turned off, American civilians provided extra food and fuel to the war effort. The United States government engaged in a massive propaganda campaign to raise troops and money. Where dissent was apparent, it was stifled, prompting many to question whether American civil liberties were in jeopardy. In the end, the war was won, but the peace was lost. The Treaty of Versailles as presented by President Wilson was rejected by the Senate. Two dangerous decades of political isolationism followed, only to end in an ever more cataclysmic war.
Explanation:
B) spread of communist ideas :)
If i remember correctly he wanted them to "fight back"
