World war i started in 1914, but the united states did not join until 1917. explain why the united states finally decided to join the war on the side of allies.

The reason the US decided to join the war was because of the Germans and there decision to continue the policy of unrestricted submarine warfare.

this means that germany had to pay the allied countries. reparations are/is essentially payment for something that they have done wrong, so after ww1, germany was forced to pay reparations so they could replenish the allied countries resources' that they had lost during the war.