I am not sure what exactly you want to receive as an answer but Ill give 2 examples.
After the rise of the Third Reich Jewish people were forced to migrate from Germany to neighboring countries and a lot of them in fact fled to United States including the famous scientist Albert Einstein.
The other example is the forced migration of Native Americans during the settlement and colonization by the American Colonies as they were trying to go farther down the continent.
In muslim society social groups were based on religion
I believe it would be politics, education, and voting right
Answer:
From what I remember, it was a revolution that overthrew the Czar and the government. The Czar wasn't very popular after the first world war, they lost a lot of people. The German's sent a radical named Vladimir Lenin back to Russia to get the Russians in a civil war. Backed by the Germans and the disapproval of the Czar, it wasn't hard for the people to listen to the "man of the people" Lenin and eventually overthrow the government.