Why were so many cities able to develop between the Tigris and Euphrates rivers?

It developed as a reaction to the impact of european colonialism in africa on peoples of african descent. in the  mid-20th century, activists in africa adopted pan-africanism as a rallying cry for independence from colonial rule. some african pan-africanists sought to unite the continent as one independenthope it was useful

He's too busy doing aaa games to be doing anime.