Question

Which of the following are most suitable indicators of SO${}_2$ pollution in the environment?

• A. Lichens
• B. Conifers
• C. Algae
• D. Fungi

Answer 1

The correct option is A Lichens

Lichens are the most suitable bio-indicators for air pollution, especially sulfur dioxide pollution since they derive their water and essential nutrients mainly from the atmosphere rather than from the soil. If the air is clean, shrubby, hairy and leafy lichens become abundant. A few lichen species can tolerate quite high levels of pollution and are commonly found on pavements, walls and tree bark in urban areas. The most sensitive lichens are shrubby and leafy while the most tolerant lichens are all crusty in appearance.

So the correct answer is 'Lichens'.