Answer:
Tigris and Euphrates
Explanation:
While Mesopotamia's soil was fertile, the region's semiarid climate didn't have much rainfall, with less than ten inches annually. This initially made farming difficult. Two major rivers in the region -- the Tigris and Euphrates -- provided a source of water that enabled wide-scale farming.
Religion was central to Mesopotamians as they believed the divine affected every aspect of human life. Mesopotamians were polytheistic; they worshipped several major gods and thousands of minor gods. Each Mesopotamian city, whether Sumerian, Akkadian, Babylonian or Assyrian, had its own patron god or goddess.
Unity between the countries for each to work together.
