Although southern Mesopotamia is a hot, desert region, why was it able to become the cradle of civilization? Select all that apply.

A.
Nomads developed aggressive herding techniques.

B.
Flooding of the Tigris and Euphrates Rivers brought good soil.

C.
Farmers developed technology for irrigation.

D.
Tribes built deep wells and extensive cooling structures for crops.

E.
Engineers developed ways of extracting usable fresh water from the salt water of the Persian Gulf.