1. Key Term
City-State- An independent kingdom or state made up of a city and the surrounding lands it controls.

2. Key Term
Empire- A large group of territories and people who are ruled by a single leader or nation. 

3. Key Term
Silt- A mixture of rock and soil that is carried by water that creates fertile soil that is good for growing crops. 

4. Key Term
Irrigation- The artificial application of water to land.

5. Key Term
Levee- A ridge or embankment built along the edges of a river or stream to prevent flooding.

6. Key Term
Dam- A barrier that people build across rivers or other bodies of water so they can store the water or move it to another location.

7. Key Term
Scribe- A person who was educated and wrote books or other documents by hand.

8. Key Term
Commerce- The act of buying and selling goods and services.