Why are amphibians good biological indicators?

amphibians are known as biological indicators. When the environment gets polluted from pesticides or ozone depletion they are the first to be affected. Since most amphibians breathre through their skin and absorb water that way the amphibians can die from the pesticides that are put in water. Sometimes they can even cause birth defects for example a five-legged frog might occur, because of this their population is decreasing. When people discover what is happening to them, we all know that this is what we are doing to them. We made the ozone layer thinner, we put pesticides in water.