Which of the following describes the people who first settled on the plain of the Tigris-Euphrates valley in 7000 B. C? A people fleeing the Assyrian army
B. Sumer farmers who raised livestock on a seasonal basis
Chunter-gatherers who settled temporarily during planting season
D. hunter-gatherers who depended on their environment for food

D. hunter-gatherers who depended on their environment for food

Explanation:

Those who first settled on the plain of the Tigris-Euphrates were hunter-gatherers who depended on their environment for food. As of 7000 B.C, they had not already developed a proper farming system.

It was not until 4000 B.C when they began building farming villages in which they depended on the rains and later built irrigation systems to help them plant and harvest crops. They had to build the irrigation systems because of the irregularities of the natural rain between the summer and winter periods as well as the flooding that wiped off their homes and crops.

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