Answer:
Waves meet the shore and cause the crest to spill over the trough.
Explanation:
This activity creates a back and forth movement of the sand which causes them to settle at a certain area below the water.
Sub-Saharan Africa's equatorial area is known as Equatorial Africa. There are 13-14 nations, so I'm guessing you want Ethiopia, Rwanda, Kenya, and Somalia, which are the most well-known. Savannas in the north and south, as well as mountains and tropical rain forests, characterize the landscape.
I think that it was a siege