| A | B |
|---|
| carbon dioxide-oxygen cycle | a natural cycle in which plants and other producers use carbon dioxide and produce oxygen, and animals, plants, and other living things use oxygen and produce carbon dioxide |
| cell respiration | the process of using oxygen to release energy from food |
| condensation | the process by which a gas changes to a liquid |
| evaporation | the process by which liquid water changes to water vapor |
| food chain | the path of energy transfer from one living organism to another in an ecosystem |
| food web | the overlapping food chaings that llink producers, consumers, and decomposers in an ecosystem |
| nitrogen cycle | the cycle through which nitrogen changes into compounds that can be used by living things and then returns to the atmosphere |
| proteins | organic compounds that form the structure of and control the processes that take place in living things |
| water cycle | a continuous process in which water moves between the atmosphere and Earth's surface, including the use of water by living things |
