Three factors - Temperature, Climate and Fertile Land causes large clusters of people to inhabit South, Southeast and East Asia.
The Fertile Crescent is thought the country of cultivation. Civilizations formed by a line of watersheds, beginning with the Nile River valley and extending up the Mediterranean coast, eastward near Iraq and southward by the Tigris and Euphrates streams until entering the Persian Gulf.
Nomadic peoples resided by the lush river banks to harvest wild wheat and barley, growing the world’s first producers. This signified a major transformation in the lifestyle of ancient humans, who till that point had remained by following their food as hunter-gatherers. In cultivation, people discovered to support themselves by managing the natural surroundings.
