Earth´s Atmosphere

                                                                         Vocabulary#13
renewable resource: a resource that can be replaced in a short period of time.

ozone layer: a layer of ozone gas in the atmosphere that screens out much of the Sun´s UV rays.

fossil fuel: a fuel formed from the decay of acient forms of life.

smog: a mixture of smoke and fog.

acid rain: moisture that falls to Earth after being mixed with wastes from burned fossils fuels