What factors led to the increase use of slave labor in virginia?

Slavery in Virginia dates to 1619,[1] soon after the founding of Virginia as an English colony by the London Virginia Company. The company established a headright system to encourage colonists to transport indentured servants to the colony for labor; they received a certain amount of land for people whose passage they paid to Virginia.[2]

African workers first appeared in Virginia in 1619, brought by English privateers from a Spanish slave ship they had intercepted. As the Africans were baptized Christians, they were treated as indentured servants. Some laws regarding slaveryof Africans were passed in the seventeenth century and codified into Virginia's first slave code in 1705.[3] Among laws affecting slaves was one of 1662, which said that children born in the colony would take the social status of their mothers, regardless of who their fathers were. This was in contrast to English common law of the time, and resulted in numerous generations of enslaved mixed-race children and adults, some of whom were majority white. Among the most notable wereSally Hemings and her siblings, fathered by planter John Wayles, and her four surviving children by Thomas Jefferson.

b)

it created free trade throughout the colonial territories.