| Word | Meaning |
| Water Cycle | the change of water from one state to another as it moves between the Earth's surface and atmosphere |
| Nitrogen Cycle | the movement of nitrogen between organisms anf their surroundings |
| Carbon Dioxide & Oxygen Cycle | the movemrnt of carbon dioxide and oxygen between organisms and the air |
| Respiration | the process of breathing in air to get oxygen and breathing out wastes |
| Carbon Dioxide | a gas made of carbon and oxygen atoms that plants need for photosynthesis |
| Evaporation | the process of changing from a liquid to a gas |
| Precipitation | water that falls to Earths surface as rain, snow, sleet, or hail |
| Condensation | the process of changing from a gas to a liquid |
| Ground Water | water that collects underground in cracks and spaces in rock |
| Water Vapor | the gas state of water |