19. What was an important factor leading the United States to
enter the First World War? (5.4)
A. the existence of treaties between the United States, Great
Britain, and Austria-Hungary
B. the United States policy of opposing communism
C. German submarine attacks on United States shipping
D. Russian attacks on United States settlements in the Aleutian
Islands
Answer: Germany's resumption of submarine attacks on passenger and merchant ships in 1917 became the primary motivation behind Wilson's decision to lead the United States into World War I.