What caused the slave population in the Chesapeake colonies to grow?

Slaves formed families and had children.

Slaves formed families and had children, is the right answer.

Explanation:

Since the economy of Chesapeake revolved around tobacco thus it relied heavily on the slave labor. In the Chesapeake region, slavery began around 1619, at the time when a Dutch selling craft bringing 20 African men accessed Jamestown, Virginia. In the following years, the slave trade grew immensely. The main reason for this was that slaves formed families and had children. As a result of family bonding among slaves, the slave population grew extensively in Chesapeake.