| A | B |
|---|
| complex | arranged in a difficult way |
| Mesopotamia | in ancient times, the geographic area located between the Tigris and Euphrates Rivers |
| Tigris River | one of the two largest rivers in Southwest Asia that flow from mountains in Turkey to the Persian Gulf |
| Euphrates River | one of the two largest rivers in Southwest Asia that flow from mountains in Turkey to the Persian Gulf |
| Sumer | an area in southern Mesopotamia, where cities first appeared |
| reliable | dependable |
| irrigation | a means of supplying land with water |
| levee | a wall of earth built to prevent a river from flooding its banks |
| canal | an artificial waterway |
| reservoir | a place where water is collected and stored for use |
| silt | fine particles of rock |
| dispute | a strong disagreement |
| city-state | an early city that was like a small, independent country with its own laws and government |
| stele | an upright slab of stone inscribed with letters and pictures to depict important events |
