How can students detect air and water pollution？A．They look for mosses and lichens and dra

How can students detect air and water pollution？

A．They look for mosses and lichens and draw the conclusion according to the number and quality of the species.

B．They go to the fields to measure the quality of air and water.

C．They set up experiments to investigate the substances in air and water.

D．They look for several kinds of species in the field, produce diagrams and draw conclusions.