replaced naturally and can be used again

Earth that has a limited supply and cannot be replaced

in the geological past from the remains of living organisms

a metal or valuable mineral can be profitably extracted

the conservation of free-falling water to electricity

generated and stored in the earth

of pollution from which pollutants are discharged

snowmelt running over land and picking up man-made pollutants

surface of an area of land, or building/structure

temperature of the Earth's atmosphere & its oceans

the natural environment, ecosystems, vegetation, & wildlife

used as a plant fertilizer

into reusable material