The south had very flat and fertile land along with its mild temperatures which made it perfect for farming whereas the north had very rugged terrain and cold temperatures during the winter which made it not ideal for farming. Because the south was great for farming they needed slaves to farm the crops for them which made the south need much more slaves than the north.
Because of the trading posts in Lisbon, it became the only entrance point for Asian goods into Europe. It was either that or deal with the Arab traders through the middle east and that was not economically viable, so they all started trading with Portugal.
"<span>b. a dynasty established by samurai that sought to limit trade with foreign nations in order to boost the economy and create national unity" would be the best option, although the economic isolationist policies were not enforced for long.</span>
