What's the oldest religion ever?

Please help, its due in 2 days and I dont know it..

To solve their problems, mesopotamians used irrigation, a way of supplying water to an area of land. to irrigate their land, they dug out large storafe basins to hold water supplies these ditches brought water to the feilds. to protect their feilds from flooding, farmers built up the banks of the tigris and euphrates.hope ths !

Read your textbook to answer that question