| A | B |
|---|
| Natural Resources | Earth materials used to make products |
| Renewable resources | soil, wood, and water |
| Planned activity | Farming: crops use up nutrients |
| Causes of soil erosion | wind, water, removal of vegetation |
| Erosion | The process that wears away surface materials and moves them from location to another |
| Climate | How fast weathering occurs |
| To increase erosion | removing plants |
| Air pollution | burning fossil fuels |
| Ice wedging | water freezing and thawing |
| Mechanical weathering | ice, tree roots, and water |
| difference between mechanical weathering and chemical weathering | only one changes the chemical composition of a rock |
| Fossil fuels | natural gas, oil, and coal |
| solar energy | energy from the sun |
| Hydroelectric | electricity produced by waterpower |
| Geothermal | energy from hot magma |
| contour farming | planting along the natural contours of the land on gently slopes |
| no-till farming | leaving plant stalks undisturbed in the field to cover soil |
| Agents of erosion | gravity, air, water, and ice |
