The correct answer to this open question is the following.
The impact of farming on the development of the Mesopotamian civilization was that Sumerians learned to develop agricultural techniques and how to take advantage of the flooding of the rivers to have fertile soil to grow crops in ancient Sumeria. This generated a great impact because farming allowed humans to settle in one territory, instead of continuing to be nomads.
Sumeria is considered to be the oldest civilization on planet Earth. Sumerians settled in the middle of the Euphrates and Tigris Rivers, in modern-day Iraq, in the Middle East Region. The impact of farming allowed Sumerians to establish important and powerful city-states such as Kish, Eridu, Ur, Lagash, Uruk, and Nippur.