| A | B |
| fossil fuel | energy source formed from the buried remains of decayed plants & animals that lived hundreds of million of years ago |
| acid rain | highly acid droplets formed when gases produced by the burning of fossil fuels combine with moisture in the clouds |
| smog | air pollution caused by automobile exhaust, burning coal or by other means, resulting in air that is unhealthy to breathe |
| natural resource | material from the environment that people use to carry on their daily lives |
| renewable resource | a natural resource, such as trees or soil, that can be replaced by natural cycles or processes |
| biomass energy | energy that is released when plants & animal products are burned |
| nuclear energy | energy released by splitting apart or the joining together of atoms of certain elements |
| solar energy | energy from the sun |
| non-renewable resource | a natural resource, such as oil or natural gas, that cannot be replaced by natural processes |
| geothermal energy | energy that comes from heat from the earth's hot interior |
| hazardous waste | waste substances that are very harmful to humans & other organisms |
| conservation | wise use of natural sources so that they will not be used up too soon or used in a way that will damage the environment |
| contour farming | farming method in which a slope is plowed horizontally across its face to avoid erosion |
| depletion | process in which nutrients are washed away from the soil by water |
| endangered species | species in danger of becoming extinct |
| erosion | process in which soil is carried off by water or wind |
| diurnal | organism that is active during the day |
| nocturnal | organism that is active during the night |
| exstinction | process by which a species passes out of existence |
| groundwater | underground water |
| hydroelectric plant | plant that uses energy from moving water to produce electricity |
| litter | material that is disposed of improperly |
| nuclear fission | process in which atoms of the element uranium are split to release energy |
| nuclear fusion | process by which atoms combined & energy released |
| pesticide | chemicals used to kill harmful insects or other pets |
| petroleum | liquid fossil fuel |
| pollution | introduction of harmful or unwanted substances into the environment |
| radioactive materials | material given off during neclear fission process that is harmful to life |
| strip cropping | farming method in which strips of cover crops are grown between strips of other crops to hold down the soil |
| temperature inversion | atmosperic condition in which a layer of cool air containing pollutants is trapped near the ground under a layer of warm air |
| terracing | farming method in which a slope is made into a series of level plots in steplike fashion to avoid erosion |
| thermal pollution | release of heat into the environment |
| topsoil | rich upper layer of soil |
| toxic | poisonous |
| watershed | lane area in which surface runoff drains into a river or system of rivers & streams |
| windbreak | row of trees planted between fields of crops to prevent erosion due to wind |
| crop rotation | farming method; alternating growth of different crops each year/same land |