The key factor in the decision of the United States to enter World War I was its long-standing friendship with Great Britain. its desire to acquire German colonies in the Pacific. the political ambition of Woodrow Wilson. Germany's resumption of unrestricted submarine warfare against the United States.

Germany's resumption of unrestricted submarine warfare against the United States.

Explanation:

The world War I (WWI) was a period of battle between various countries from 1914 to 1918. It started formally on the 28th of July, 1914 and ended on the 11th of November, 1918.

The key factor which prompted and influenced the decision of the United States of America to enter World War I (WWI) was because Germany resumed the use of unrestricted submarine warfare against the United States.

A subchaser also known as a submarine chaser refers to a little but very fast naval vessel which was designed specifically for anti-submarine warfare during the World War I.

During the World War II by late 1942, the German submarines (U-boats) were destroyed by the U.S Navy subchasers in the Atlantic. The subchasers that was used by the U.S Navy were the SC-497 class and PC-461 class subchasers which had anti-aircraft guns and machine guns.