| A | B |
|---|
| ecosystem | a community of all the living things in an area and the environment in which they live |
| wetland | an area where the soil is usually wet or covered with water |
| food web | all of the feeding relationships within an ecosystem. |
| freshwater | made up of water that is fresh, not salty; |
| glacier | a large mass of ice found near Earth’s poles or in a high, cold mountain valley |
| habitat | the natural environment in which a plant or animal lives |
| invasive species | nonnative plants and animals that invade an ecosystem |
| non-point-source pollution | pollution that does not come from a single location, but rather from many sources such as runoff from farms |
| point-source pollution | water pollution from a single place, such as a discharge pipe at a plant that treats sewage |
| pollutant | something that pollutes, or damages, air, soil, or water |
| pollution | damage to the natural environment caused by harmful substances; also refers to harmful substances |
| 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 |
| toxic chemical | a chemical that is poisonous to humans or other living things |
| watershed | a geographic area that includes all of the land and waterways that drain into a body of water |
| food chain | a series of plants and animals, each of which depends on the one below it for food. A food chain usually forms part of a much larger food web. |
