Why might a post classical civilization want to conquer Mesopotamia? It's fertile land provided the foundation for the first human civilizations and its access to the Persian Gulf and location between Europe, Asia, and Africa made it a center of trade.
Most likely due to the movement of plate tectonics. They are plates of earth under the ocean that move occasionally, over the years this is probably what happened. Plate tectonics are also the cause of most earthquakes and even tsunamis. Erosion could also play a factor in this as well.
Answer:
Níger, Somalia y Mali son los países que lideran el ranking