Answer:
abolitionists
those who believed slavery was bad for white workers
small farmers
Explanation:
Brown v. Board of Education was a landmark case in which it was finally proven that segregation in institutions of education was highly unconstitutional, so you could say that that is the greatest effect since it made other schools become open for everyone as well.
Heinrich Himmler implemented Hitler's Holocaust plan to uproot eastern Europeans and send German peasants to colonize their land. They were Nazis and Himmler was responsible for the Holocaust, and directed the mass killing of six million Jewish people, and many other ethnicities. He later committed suicide in the British custody.
Most immigrants to the United States in the antebellum era came from Germany and Ireland.
There were various reasons why they emigrated into the States, but the most important one was civil unrest in their native countries. Also, they couldn't find jobs home, and they heard that America is a land of freedom and opportunity, so obviously they wanted to be successful too.
