| A | B |
|---|
| Carbon Cycle | The continuous exchange of carbon dioxide and oxygen among living things. |
| Climax Community | The final stage of succession in an area, unless a major change happens. |
| Compost | A mixture of dead plant material that can be used as fertilizer. |
| Condensation | The changing of a gas into a liquid. |
| Endangered Species | A species that is in danger of becoming extinct. |
| Estuary | The boundary where a freshwater ecosystem meets saltwater ecosystem. |
| Evaporation | The boundary where a freshwater ecosystem meets saltwater ecosystem. |
| Ground Water | Precipitation that seeps into the ground and is stored in tiny holes, or pores, in soil and rocks. |
| Nitrogen Cycle | The continuous trapping of nitrogen gas into compounds in the soil and its return to the air. |
| Pioneer Species | The first species living in an otherwise lifeless area. |
| Precipitation | Any form of water that falls from the atmosphere and reaches the ground. |
| Runoff | Precipitation that flows across the land's surface or falls into rivers and streams. |
| Succession | The process of one ecosystem changing into a new and different ecosystem. |
| Water Cycle | The continuous movement of water between Earth's surface and the air, changing from liquid to gas to liquid. |
| Watershed | Area from which water is drained; a region that contributes water to a river or river system. |
