Which of these was a factor in the United States entrance in World War I?

Question

Responses

A

the invasion of Poland

the invasion of Poland

B

Japan's invasion of China

Japan's invasion of China

C

The Axis threat to the Panama Canal

The Axis threat to the Panama Canal

D

German unrestricted submarine warfare

Answer 1

D

German unrestricted submarine warfare was a significant factor in the United States' entrance into World War I. It led to the sinking of ships with American passengers and cargo, most notably the Lusitania in 1915, which heightened tensions and contributed to America's decision to enter the war in 1917.