| Term | Definition |
| biosphere | the regions of the surface and atmosphere of the Earth (or other planet) where living organisms exist |
| atmosphere | the envelope of gases surrounding any celestial body |
| geosphere | The mostly solid, rocky part of the earth; extends from the center of the core to the surface of the crust., |
| hydrosphere | the watery layer of the earth's surface, is made up of all the water on Earth in the air, the ocean the lakes, glaciers, rivers and streams, and underground |
| fluid | A substance that has the ability to flow |
| lithosphere | a rigid layer made up of the uppermost part of the mantle and the crust |
| reservoir | a place where something is stored |
| detritus | dead organic matter |
| photosynthesis | the process by which green plants and certain other organisms synthesize carbohydrates from carbon dioxide and water using light as an energy source and usually releasing oxygen as a byproduct |
| respiration | Process where animals and plants break down sugar molecules to release energy; carbon dioxide and water are released as byproducts |
| carbonate sediments | small particles containing carbon and oxygen in the form of CO3 |
| fossil fuels | Combustible materials such as oil, coal and natural gas that are composed of the remains of formerly living material |
| combustion | a process in which a substance reacts with oxygen to give energy in the form of heat and light |
| limestone | a sedimentary rock consisting mainly of calcium carbonate that was deposited by the remains of marine animals |
| cycle | a sequence of events that repeats itself |
| biogeochemical cycle | chemicals are cycled in the atmosphere, hydrosphere, lithosphere, and biosphere |
| closed system | a system that allows the exchange of energy, but not matter, between the system and its surroundings. |
| open system | a system that can exchange both matter and energy with its surroundings |