| A | B |
|---|
| natural resources | anything useful that comes from the earth. |
| nonrenewable resource | once it's used up, it's gone forever. |
| renewable resource | nature replenishes this resource |
| irrigation | supplies water to dry areas so that crops can grow |
| depletion | removal of nutrients from the soil. |
| crop rotation | alternating crops on the same land to prevent depletion. |
| erosion | carrying off of soil by water and wind |
| desertification | when grasslands become deserts as a result of erosion as a result |
| water cycle | how water is renewed, the hydrologic cycle |
| ground water | water found beneath the Earth's surface, water in the aquifer. |
| desalination | taking the minerals out of ocean water so as to make fresh water for drinking. |
| mineral | naturally occuring chemical substance found in the earth. |
| ore | a mineral that can be mined for profit. |
| alloy | substance made of two or more minerals |
| terracing | planting a slope in a step like fashion to prevent erosion. |
