Class struggle and political revolution is necessary for socialism to emerge. They think that everyone will just adopt it, without struggle or a fight, if it's represented convincingly.
Biological warfare was effective against the Inca because there immune system's were not used to that type of diseases that Europeans brought over. There are very susceptible to disease and were wiped out quickly
In the early 1900's, 6 million African Americans emigrated form the rural south of the US to the northeast, mid-west and west and thus began an urban existence in many of the cities in these areas so became important politically due to their numbers and their strong support of the civil rights movement later on.
