Vocabulary #15

1. renewable resource: a resource that can be replaced in a short period of  time.
2. ozone layer: a layer of ozone gas in the atmosphere that screens out much of the Sun's UV rays.
3. fossil fuel: a fuel formed from the decay of ancient forms of life.
4. smog: a mixture of smoke and fog.
5. acid rain: moisture that falls to Earth after being mixed wiyh wastes from burned fossil fuels.