Across
- 3. a gradual increase in the earth's temperature generally due to the greenhouse effect caused by increased levels of carbon dioxide, CFCs, and other pollutants
- 4. an organism that cannot produce its own food and must eat other plants and/or animals to get energy
- 5. the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems
- 7. water which collects as droplets on a cold surface when humid air is in contact with it.
- 10. any liquid or frozen water that forms in the atmosphere and falls to Earth
- 11. describes how carbon moves between the atmosphere, soils, living creatures, the ocean, and human sources
- 12. a chemical or natural substance added to soil or land to increase its fertility.
Down
- 1. the process of burning something.
- 2. the process of converting natural nitrogen compounds into ammonia
- 6. a biological community of interacting organisms and their physical environment.
- 8. Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow
- 9. have the ability to break down dead organisms into smaller particles and create new compounds
- 12. nonrenewable sources of energy formed from the organic matter of plants and microorganisms that lived millions of years ago