<span>The issue of slavery was largely responsible for the party realignment that followed the election of Abraham Lincoln in 1860 because Abraham was the one who fought for the rights of black people in USA and he was the one who killed the racism.</span>
The Ice Age had a great effect on where people settled in americans since they were only able to reach North America through the Bering Land Bridge, which was only frozen due to the extremely low temperatures. Without this they would have had no way to leave Siberia.
I am not so sure what you mean by "what kinds of unions were formed", but if you're talking about the Civil War then I think the unions were Confederate and Union. The Confederates wanted to run the country with slavery while the Union fought against slavery. Do not quote me on that though.
