| A | B |
|---|
| acid rain | rain that has acids from pollution and that harms living things |
| biodegradable | something that is able to be broken down, or decomposed |
| conservation | saving and wise use of natural resources |
| fossil fuels | fuels such as coal, oil, and natural gas that formed millions of years ago |
| global warming | an increase in the Earth's average temperature |
| greenhouse effect | trapping of the sun's heat in Earth's atmosphere by carbon dioxide and other gases |
| natural resource | material from Earth that people use |
| nonrenewable resource | natural resource that cannot be replaced once it is used up like coal |
| ozone | gas that is a form of oxygen; it forms a protective layer high in Earth's atmosphere, but it can be a pollutant if near the surface |
| pollutant | harmful substance in the air, land, or water |
| pollution | damage done to the environment by the addition of pollutants |
| recycle | to treat or change waste so that it can be used again |
| renewable resource | natural resource that can be replaced as it is used such as wind power |
| smog | a result of air pollution caused by exhaust gases reacting with sunlight |
