| A | B |
|---|
| alternative energy source | a source of energy other than a burning fossil fuel |
| geothermal energy | Earth's internal energy |
| biomass | plant matter or animal waste that can be used as a source of energy |
| desallination | getting fresh water from seawater |
| water cycle | the continuous movement of water between Earth's surface and the air, changing from liquid to gas to liquid |
| groundwater | water that seeps into the ground into spaces between bits of rock and soil |
| water table | the top of the water-filled spaces in the ground |
| aquifer | an underground layer of rock or soil filled with water |
| spring | a place where groundwater seeps out of the ground |
| well | a hole dug below the water table that water seeps into |
| reservoir | a storage area for freshwater supplies |
| 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 ancient forms of life |
| smog | a mixture of smoke and fog |
| acid rain | moisture that falls to Earth after being mixed with wastes from burned fossil fuels |
