Awatershed is the area of land where all of the water drains off and eventually combines at a central point. as water runs off it picks up different types of surface pollution left over from agricultural, industrial, commercial, and other types of human activity. why does the pollution in a watershed have such a heavy impact on its inhabitants?

1. pollution does not affect the inhabitants of a watershed
2. the water combines and the pollutants becomes less concentrated
3. the water combines and the pollutants becomes more concentrated
4. the species that inhabit the watershed must have the pollution in order to survive