Answer:
In 1947, President Harry S. Truman pledged that the United States would help any nation resist communism in order to prevent its spread. His policy of containment is known as the Truman Doctrine. The Truman Doctrine demonstrated that the United States would not return to isolationism after World War II, but rather take an active role in world affairs. To help rebuild after the war, the United States pledged $13 billion of aid to Europe in the Marshall Plan.
The United Stated had to contain communism from spreading through out Berlin, Korea, and Cuba.
Explanation:
Because it had a great effect on history.
The Zimmerman Note was a note sent from Germany to Mexico asking Mexico to align itself with German interests. If the US entered the war and if Mexico opposed the US, the reward would be Arizona California and one other state -- perhaps Texas. It was a major contributor to the declaration of war on Germany by America.
The sinking of the Lusitania was another major event. When the Lusitania was sunk, 2000 people were affected.
Submarine warfare really aggravated the US. Many merchant ships were sunk.
Answer: B
The conflict because of the Indian an Americans