Why did the americans join war world 1 ?

Explanation:

Well because after Germany warned the US not to send any ships in European waters and warned American not to board any vessels in the area Americans chose to board the Lucitania anyway and the us wanted in the war so when the Lucitania was bombed that was our excuse to enter the war.

The Germans wanted the Mexicans to attack USA to avoid their intervention but the Americans found out about it and interviened.

b

explanation:

"germany's geographic location was an advantage when it was on the offensive in the war because it was situated next to an extremely wide river, the rhine, which was difficult for the allies to cross."