| A | B |
|---|
| Huang He | This is also called the Yellow River. |
| Nile | This river is located in Egypt. |
| Indus | This river valley is in Pakistan and India. |
| Tigris and Euphrates | This river valley is located in present-day Iraq. |
| specialization | This is the term for the development of occupations. |
| cultural diffusion | This is the exchange of goods, ideas and customs among different cultures. |
| Africa | The Egypt is on this continent. |
| Asia | Iraq is on this continent. |
| law and government | People developed this when they needed to develop rules about gathering, storing, and distributing grain fairly. |
| engineering | People needed these skills to create irrigation systems and control flooding. |
| Huang He | Of the four river valleys, this one had the most rain. |
| Nile | Of the four river valleys, this one had the least amount of rain. |
| building and architecture | People developed these skills when they needed to create storehouses for grain. |
| writing and mathematics | People developed these skills when they needed to keep records of how much grain they had. |
| 4500 BC | Approximately when did the civilization in the Tigris and Euphrates River Valley develop? |
| 2500 BC | Approximately when did the civilization along the Nile River develop? |
