Why did lifelong slavery based on race develop in colonial America

As British colonists became convinced that Africans best served their demand for labor, importation increased. By the turn of the eighteenth century African slaves numbered in the tens of thousands in the British colonies.

Explanation:

the answer is true .

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.