Why did the wars and revolutions in china and eastern europe lead to increased immigration to the united states?

The correct answer is that they disrupted the lives of people in those regions. For example, when the communists came they took away land and farms and companies from people who had them because they were considered to be public property according to communists, so they ran away to the US where they could run their own businesses and have their own land.

Democracy and darwinism would be my answer.