Question

Lichens are used to sense air pollution as

• A. Their colour changes
• B. They are sensitive to the levels of contaminants like sulphur dioxide
• C. pH checked by these
• D. None of these

Answer 1

The correct option is B They are sensitive to the levels of contaminants like sulphur dioxide

Lichens are mutualistic associations of a fungus and an algae or cyanobacterium and occur as crusty patches or bushy growths on trees, rocks and bare ground. The lichens are useful bio indicators for air pollution, especially sulphur dioxide pollution since they derive their water and essential nutrients mainly from the atmosphere rather than from the soil. They react to air pollutants all year round.