| A | B |
|---|
| natural resource | A source or organism found in nature that people can use. |
| renewable resource | A natural resource that can be replaced in nature at the same rate it is used. |
| nonrenewable resource | A natural resource that exists in a fixed amount or that is used up faster than it can be replaced in nature. |
| fossil fuel | A nonrenewable energy source formed from ancient plants and animals buried in Earth's crust for billions of years. |
| conservation | Protecting, restoring, and managing natural resources so they last as long as possible. |
| recycling | Recovering materials that people usually throw away. |
| nuclear fission | The nucleus of a radioactive atom is split, forming whiter elements and releasing a huge ammount of energy. |
| hydroelectric energy | Electricity produced by moving water. |
| solar cell | A specially constructed sandwich of silicon and other materials that converts light energy to electricity. |
| geothermal energy | Energy produced by heat within earth's crust. |
| biomass | Organic matter, such as plant and animal waste, that can be used as fuel. |
| hydrogen fuel cell | The device that produces electricity by seperating hydrogen into protons and electrons. |
