In the lower Tigris-Euphrates Valley, __________________poisoned the fields once farmed by Ubaidians and Sumerians.
A) the Black Death
B) Neolithic herders
C) severe soil erosion
D) high levels of salts
E) animal grazing

Question

Quizplus · Accepted Answer

High levels of salts have caused soil salinization in the Tigris-Euphrates Valley, which has made farming difficult and, in some cases, impossible. This has been a major problem for thousands of years and has contributed to the decline of many civilizations in the region, including the Ubaidians and the Sumerians.

In the Lower Tigris-Euphrates Valley, __________________Poisoned the Fields Once Farmed