Answer:
The Population of the people across the Sahara region where influenced by the rain and climate change.
Explanation:
Originally the region or area in which the people lived where much of grasslands where they where able to settle down, but overtime due to climate change, the rain began to decline, and their region destroyed, they had to migrate to a new region and probably adapt to it, by been careful of the resources they had left and use in the new area of settlement.
