| A | B |
| natural resource | A material on Earth that is necessary or useful to people |
| reusable resource | product that can be used again |
| renewable resource | a resource that can be replaced over and over again |
| recycling | to treat or change something so it can be used again |
| fossil fuels | fuels made from the remains of dead plants and animals, as coal, oil, or natural gas |
| nonrenewable resource | resource that take millions of years to form |
| natural gas | a gas found deep in the earths' crust that is used for heating and cooking |
| reuse | To use something again |
| Conservation | to try and make sure there are enough of something for the future |
| soil | a mixture of tiny rock particles, minerals, and decayed plants and animal material. |
| Pollution | what happens when harmful substances get into water, air, or land |
| Erosion | occurs when weathered materials are carried away |
| Weathering | process that causes rocks to crumble, crack, and break |
| runoff | the water that flows over Earth's surface. |
| reduce | To make less or use less of something |