The role of a watershed is to
a. purify water.
b. act as a drainage area.
c. collect fish from rivers and streams.
d. protect wetland areas.

The right answer is B. act as a drainage area.

A watershed or watershed is the space drained by a watercourse and its tributaries. All the waters that fall into this space converge towards the same exit point called an outlet: stream, lake, sea, ocean, etc.

The watershed is bounded by a watershed that often corresponds to the ridge lines but not always. Generally a watershed develops beyond the ridge lines. A watershed is a divergent line of slopes. Rainwater on both sides of this line flows in two different directions, carrying with them dissolved or suspended elements such as sediments and pollution.

c.more precipitation,but only when emission levels.