Explain how and why slavery developed in the american colonies

The need for farm labour in the hot climate of the Southern States.

Explanation:

Settlers found that they were unwillingly and unsuited to working in the hot climate of the Southern States to raise crops.

The plantation owners needed workers in their fields. Black slaves were imported from Africa. These slaves being black could not escape and fade into the general population. The slaves at first could not speak English, so they could be held easily in slavery. The Africans coming from a similar climate were able to work in the hot climate of the Southern States.