What was one way that slavery in africa differed from the institution of slavery in europe or the united states?

Why might the spanish government have approved of the encomienda system? a the system allowed for fair treatment of all under it, leading to a happy and prosperous colony. b the system used natives as slaves which meant the government was able to maximize their profit of exported goods. c the system allowed for mostly profitable trade within the different colonies. d the system was a great example of how to successfully run a colony, making spain a world power.