Final answer:
The Zimmermann Telegram, sinking of the Lusitania, and unrestricted submarine warfare led to the U.S. joining World War I.
Step-by-step explanation:
The events listed above: the Zimmermann Telegram, the sinking of the Lusitania, and unrestricted submarine warfare, were all significant factors that led to the U.S. entering into World War I.
The Zimmermann Telegram was a secret message sent by Germany to Mexico, proposing an alliance against the United States. When the telegram was intercepted and decoded by the British, it caused outrage in the U.S. and fueled anti-German sentiment.
The sinking of the Lusitania, a British passenger ship, by a German submarine in 1915 also contributed to increased tensions between the U.S. and Germany. The loss of American lives in the incident further swayed public opinion in favor of entering the war.
In response to these events, President Wilson issued his Fourteen Points, a set of principles aimed at promoting peace and stability after the war. They outlined goals such as self-determination for nations and the establishment of the League of Nations.
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