Depends on what you mean slavery -(freedom) was the act of African Americans fighting for their will rights and "freedom"
And freedom as a nation is the ability to do as you please (to a limit) and not have to worry about anything like slavery, not soon anyways.
The correct answer to this is Natural Resources. <span>In the mid to late 19th century, natural resources were heavily exploited, especially in the West. Land speculators and developers took over large tracts of forests and grazing land. Acreage important to waterpower was seized by private concerns.
Hope this helps :)</span>