Question

Which organisms are found on the bark of trees as indicators of a pollution-free environment?

Answer 1

1. The organisms that are found on the bark of trees as indicators of a pollution-free environment are lichens and mosses.
2. These organisms are sensitive to sulfur oxides (SO₂) and cannot grow in the region that possesses SO₂ or other oxides of sulfur.
3. So that indicates that the absence of these organisms shows pollution or a polluted area.