| A | B |
|---|
| trade winds | steady winds in tropical latitudes that blow toward the equator from both the north and south |
| marginal land | land that isn't well suited for growing crops |
| pastoral nomads | groups of herders who move with their animals from place to place in search of pasture and water |
| desertification | the process by which land becomes more and more dry until it turns into desert; may be caused by climate change, human activities, or both |
| erg | a great sea of sand with tall sand dunes in the Sahara |
| reg | a gravel covered desert plain |
| hammada | a high, rock-covered flatland in the Sahara |
| cash crop | a crop that is grown to be sold rather than to be consumed by the farmers and their families |
| adaptation | a change in the way of life to suit new conditions |
| shifting agriculture | clearing one area for farming for a few years and then moving on to another area when the first has lost its fertility |
