| A | B |
|---|
| glaciers | large masses of ice found high on the earth or near its poles |
| ecosystem | a community of all living things in and around the environment |
| freshwater | fresh water with no salt; also used to describe animals that live in freshwater |
| watershed | an area that includes all the land and waterways that drain into a body of water |
| food web | all of the feeding relationships within and ecosystem. |
| food chains | a series of plants and animals, each of which depends on the one below it for food |
| pollution | damage to the natural environment caused by harmful substances; also refers to harmful substances |
| point-source pollution | pollution from a single place |
| non-point source pollution | pollution that does not come from a single place, but from many sources |
| runoff | water from rainfall that is not absorbed into the soil and instead flows into streams or lakes |
| sediment | bits of soil left in a place by moving water |
| invasive species | nonnative plants and animals that invade an ecosystem |
| habitat | the natural environment in which a plant or animal lives |
| wetlands | an area where the soil is usually wet or covered with water |
