| Term | Definition |
| Slowest oxidation process | rust |
| role of fossil fuels in the carbon cycle | they are released and freed when the fossil breaks down or is burned |
| Besides nitrogen-fixing bacteria, ___ changes nitrogen into a form that is easier for plants to use | lightning |
| Some animals get the nitrogen they need from | plants they eat |
| We should protect the rainforests because | they produce 1/3 of the earth's oxygen |
| Nitrogen makes up about ___of the air around us | 78% |
| Animals help recycle carbon atoms by | exhaling carbon dioxide into the atmosphere |
| decomposers | feeds on dead organisms and release carbon dioxide as a by product of respiration |
| The amound of exygen in our atmosphere | 21% |
| Producers in carbon cycle | green plants which combine carbon, oxygen, and hydrogen atoms during photosynthesis |
| Carbon | most abundant element on earth |