| Term | Definition |
| Carbon Oxygen Cycle | the continual process of transferring carbon between Earth's living organisms and Earth's geological elements |
| Carbon | This element is found in all organic life |
| Photosynthesis | the process by which carbon dioxide is converted into carbohydrates |
| Cellular Respiration | the process by which animals break down glucose into carbon dioxide and water |
| Nitrogen Cycle | the pathway for the movement of the nitrogen among Earth's organism |
| Denitrification | the process by which bacteria convert nitrate back to Nitrogen |
| Nitrogen Fixation | a process whereby certain soil bacteria break down nitrogen and nitrogen found in in dead organic matter and convert it to wither nitrate or ammonia |
| Phosphorous Cycle | One of the slowest biogeochemical cycle |
| Hydrologic Cycle | Another name for the water cycle |
| Water Cycle | the continous circulation of water between earth's organisms, atmoshere and surface |
| Precipitation | Te process by which water return to the surface (rain. sleet, snow--etc) |
| Transpiration | The process by which plants gives off water to the atmosphere |
| Evaporation | The process by which surface liquid water is converted from a liquid to a gas |