Well, there can be three answers to this. Trade, migration, and expansion all played important roles in the spread of these things. When merchants traded, their cultures were spread, as they traded both products and information. Migration also played a role, since people migrated and then they adapted to the indigenous people's culture and the indigenous learned from them. Additionally, expansion played a role, because when people conquered other people, they forced them to accept their culture and eventually cultures mixed.
One major pull factor that contributed to the population growth shown in the urban area of northern Illinois and Indiana was "<span>racial discrimination," since many blacks in the South fled to the North in the hopes of living better lives. </span>
