ALLIED POWERS: Included leaders like, David Lloyd George, Wilhelm the 2nd, Nicholas the 2nd of Russia, Vladimir Lenin, and Woodrow Wilson. Britain, Russia, France, Italy, and the USA.
US ENTERS WAR: The sinking of the Lusitania and the Zimmerman telegram caused the US to join the allied powers. The allied powers now had a great deal of aid.
RUSSIA LEAVES WAR: So many of Russia's troops had died or been captured. This caused an armistice meaning that Russia agreed to stop fighting. So, they ended up leaving the war.