What were the causes of world war 1 and how did americans help the allies during the war? Someone help me please

Main causes of war were imperialism and militarism among European countries and rise of nationalism in certain areas of Europe. United States was a prevailing factor, that helped the Allied forces by providing certain goods to them and then from 1917 when US entered the war officially fought against Germany.

Explanation:

Before WW1 two great alliances were created in Europe - Central Powers and Entente.

Central Powers were unsatisfied with the colonial distribution and started spreading their military power.

When Franz Ferdinand was murdered, they jumped into war as they were already prepared for it.

United States were officially neutral, but from the beginning it was clear that they supported the causes of Allies.

the answer is selfishly. hope this !