Answer:
The U.S. entered World War I because Germany embarked on a deadly gamble. Germany sank many American merchant ships around the British Isles which prompted the American entry into the war.
Step-by-step explanation:
abruptly on May 7, 1915, when a German submarine sank the British ocean liner Lusitania with 1,198 people aboard, among them over 100 Americans. When Germany announced on January 31, 1917 a policy of unrestricted submarine warfare, the United States cut diplomatic ties with Germany.
First, it motivated Anglo-Americans to push back against anything German. States banned German-language schools and removed German books from libraries. Some German Americans were interned, and one German American man, who was also targeted for being socialist, was killed by a mob.