Human migration occurred because of several factors. The reasons are the following:
1.food shortages
2.War
3 Seasonal changes
4.Disease and epidemic.
Africans are nomadic people. They thrive more from their environment. They only had to stop migrating during the agricultural era, wherein they learn to plant and tend crops and started cattle herding.
Abraham Lincoln did on March 3 1865
I think it is d if I'm wrong I'm sorry