Why was south basically a self-sufficient society

Because the south continued the slavery so everyone started a war on the to stop the slavery like the north did

What document are you referring to

To solve their problems, mesopotamians used irrigation, a way of supplying water to an area of land. to irrigate their land, they dug out large storafe basins to hold water supplies these ditches brought water to the feilds. to protect their feilds from flooding, farmers built up the banks of the tigris and euphrates.hope ths !