Q42
General ScienceEnvironment & Ecology
Lichen is extremely sensitive to
- a.SO$_2$
- b.CO$_2$
- c.CO
- d.N$_2$
Answer: (A) SO$_2$
Lichens absorb water and gases directly through their surface and are killed by even low levels of sulphur dioxide, so they are used as indicators of SO$_2$ pollution. CO$_2$ and N$_2$ are normal air components, and CO is not what lichens indicate.