Answer:
When growing tobacco became a big thing.
Explanation:
Growing tobacco is something that occupies time and requires patience. The white settlers had limited time and patience, and would have preferred someone like a servant to do this work. But servants want to be payed and and that is costly. Free servants was a deal back then that's hard to beat. So slaves were taken and bought, and used for the work they preferred not to do or pay people to do.
