Answer :
Slaves were in high demand in the southern colonies because the major industry in the south was agriculture that required a large amount of labor. Because labor was at a high demand and the tasks required were difficult and menial there was a high demand for slave labor. Slave labor served as a major factor in establishing the South as an agricultural hub during this period especially with crops like cotton.
Slaves were needed in the southern colonies because the south relied heavily on agriculture. Cotton, a cash crop, was picked by slaves.