| A | B |
|---|
| complex | Arranged in a difficult way |
| Mesopotamia | In ancient times, the area located between the Tigris and Euphrates Rivers |
| Tigris River | One of the two largest rivers in Southwest Asia that flow from the 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 |
| materials | A resource that can be used to make something else |
| maintain | to keep something in good condition by making necessary repairs |
| Sumer | An area in southern Mesopotamia, where cities first appeared |
| Zagros Mountains | Mountains southwest of the Fertile Crescent |
| irrigation | a means of supplying land with water |
| levees | A wall of earth built to prevent a river from flooding its banks |
| silt | fine particles of rock |
| disputes | A strong disagreement |
| city-states | an early city that was like a small, independent country with its own laws and government |
