| A | B |
|---|
| weather | The short-term changes in the air for a given place or time. |
| climate | A region's average weather conditions over a long period. |
| prevailing winds | Winds that blow in the same direction over large areas of Earth. |
| ocean currents | Large streams of surface seawater. |
| front | The place where two air masses of different temperatures or moisture content meet. |
| monsoons | Seasonal winds that bring either dry or moist air. |
| savannas | Areas of tall grasses and scattered trees and scrubs. |
| steppes | Semidry grasslands or prairies. |
| permafrost | Permanently frozen layers of soil. |
| environment | Surroundings. |
| ecosystem | Group of plants & animals depending on each other for survival and the environment. |
| habitat | The place where a plant or animal lives. |
| extinct | To die out. |
| humus | Decayed plant or animal matter. |
| desertification | The spread of desertlike conditions. |
| natural resource | Any material in nature that people use and value. |
| renewable resources | Resources Earth replaces naturally. |
| nonrenewable resources | Resources that cannot be replaced. |
| deforestation | Clearing of trees. |
| reforestation | Planting trees to replace list forestland. |
| fossil fuels | Nonrenewable resources that formed from the remains of ancient plants and animals. |
| hydroelectric power | The production of electricity from waterpower. |
