Questions about WWI

1. World War I, or the Great War, began on June 28, 1914 after Serbian nationalist, Gavrilo Princip assassinated Archduke Franz Ferdinand in Sarajevo, Bosnia. This was the immediate cause. The war was fought between the Central Powers of Germany, the Ottoman Empire, and Austria-Hungary, and the Allied Powers of Great Britain, France, Russia, Italy, Japan, and later the United States in 1917.

2. The United States entered the war in February 1917 due to German submarine aggression in the Atlantic Ocean. After the sinking of British ocean liner Lusitania in May 1915, American public opinion was turned against Germany, and Congress passed a $250 million appropriation to prepare for war. Furthermore, Germany sunk  four more US merchant ships headed for Britain.

3. World War I came to an end after the Central Powers began losing battles along the  two fronts. The Ottoman economy and land was ruined by the war, and they were forced to sign an armistice in October 1918. Austria-Hungary signed an armistice on November 4, 1918 due to the growing nationalist movements within its borders. Germany signed an armistice on November 11, 1918, ending the war. German citizens stopped supporting the war effort and the loss of its allies left Germany with little choice but to surrender.

4. Signed on June 28, 1919, the Versailles Treaty officially ended the war under the terms that Germany give back lands it previously took from Russia, and the nation had divide up a portion of its land among France, Belgium, Poland, Denmark, and Czechoslovakia. Germany also had to reduce its army to 100,000 men, take full responsibility for the war, and pay a huge sum of money to the Allies. As part of the treaty and negotiated by President Woodrow Wilson, the League of Nations was to be formed for all nations excluding Germany. However, the United States did not ratify the treaty because joining the League of Nations would force it to give up a sizable amount of power.

5. How did World War I contribute to the commencement of World War II?
The harsh treatment of Germany under the Treaty of Versailles at the end of World War I led to building hatred and anger among the German populace that would later contribute to the start of World War II.

Sources:
Note: It was difficult to find a single source that covered all of the questions and their different parts. HISTORY covered the majority of the questions, but did not list the terms of the agreement nor the reason that the United States abstained from ratification.
1. World War I History- HISTORY
2. The Gilder Lehrman Institute of American History 

Diplomates gather for the signing of the Treaty of Versailles. Texas Tech Today