Natural Resources

3. The presence in or introduction into the environment of a substance or thing that has harmful or poisonous effects.
5. A combustible black or dark brown rock consisting mainly of carbonized plant matter, found mainly in underground deposits, and widely used as fuel.
6. A source of energy that is not depleted by use, such as water, wind, or solar power.
8. The variety of life in the world or in a particular habitat or ecosystem.
11. Relating to or produced by the internal heat of the earth.
12. Flammable gas, consisting largely of methane and other hydrocarbons, occurring naturally underground (often in association with petroleum) and used as fuel.
14. The ability to be maintained at a certain rate or level.
16. The gradual destruction of something.
18. The upper layer of earth in which plants grow, a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles.
20. The generation of electricity using flowing water.

1. Natural movement of the air.
2. Prevention of wasteful use of a resource.
4. A large area covered with trees and undergrowth.
7. A solid inorganic substance of natural occurrence.
9. A source of energy this is depleted by use.
10. A natural fuel such as coal or gas, formed in the geological past from the remains of living organisms.
13. A colorless, transparent, odorless liquid that forms the seas, lakes, rivers, and rain and is the basis of fluids of living organisms.
15. The sun’s rays as a source of energy from which power for domestic or industrial use may be generated.
17. A viscous liquid derived from petroleum, especially for use as a fuel or lubricant.
19. The invisible gaseous substance surrounding the earth, a mixture mainly of oxygen and nitrogen.