Answer:
As Jeffrey told National Geographic, “The Nile Valley and Oman's Dhofar region are both limestone plateaus, heavily affected by perennial rivers. It's logical that people moved from an environment they knew to another one that mirrored it. At the time when I'm suggesting they expanded out of Africa, southern Arabia was fertile grassland. The Indian Ocean monsoon system activated rivers, and as sand dunes trapped water, it became a land of a thousand lakes.
Explanation:
