Which best explains why flood plains encouraged settlement in the Fertile Crescent

In the fertile crescent, the most important floodplain is that of Mesopotamia, between the rivers Tigris and Euphrates.
This area of the world is not only where agriculture was first attested, but also the region where the first human civilization emerged: Sumer.
And the floodplain was crucial for this. The rivers flooded their banks with nutrients that were carried in sediments. These nutrients made the soil more fertile, allowing for easier and more productive agriculture, which produced the necessary food surpluses that are required for the development of early civilization.

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Italy had political stability, wealth, and trade.