Vietnam created a sub nation and a 'sub-leader'
C.
It was more efficient to import slaves from Africa than from other places.
Without food people would all have to go back to raising their own farms and could not support cities and without money coming in and out through the cities economy would start to collapse. No society can live without an economy so then society would fall. Also if people did stay in the cities without food supply they would die of starvation and without people there can be no society. Stable food supply is necessary for society to survive.
