Answer: irrigation systems they helped grow more food and protect their fields from over flooding
Step-by-step explanation:
To irrigate their land, they dug out large storage basins to hold water supplies. Then they dug canals, human-made waterways, that connected these basins to a network of ditches. These ditches brought water to the fields. To protect their fields from flooding, farmers built up the banks of the Tigris and Euphrates.