Question

A location with luxuriant growth of lichens on the trees indicates that the:

• A. Trees are heavily infested
• B. Location is highly polluted
• C. Location is not polluted
• D. Trees are very healthy

Answer 1

The Correct Option is C

The given question asks about the presence of luxuriant growth of lichens on trees and what it indicates about the location. Let's examine the facts about lichens and their environmental significance:

• Lichens as Biological Indicators: Lichens are symbiotic associations between fungi and algae or cyanobacteria. They are highly sensitive to air pollution, especially sulfur dioxide (SO₂). As such, they serve as excellent indicators of air quality.
• Lichen Growth and Polluted Areas: In areas with high levels of pollution, particularly sulfur dioxide, lichens are unable to survive due to their sensitivity to pollutants. In contrast, areas with low pollution levels allow lichens to grow abundantly.

Reasoning:

1. Option: Trees are heavily infested — While heavy infestation refers to the presence of pests or diseases, lichens are not pests; they are harmless and do not indicate any tree infestation.
2. Option: Location is highly polluted — This is incorrect because lichens cannot thrive in highly polluted environments. They die off quickly when pollution increases, particularly with sulfur dioxide.
3. Option: Location is not polluted — This is the correct answer. Luxuriant growth of lichens signifies good air quality as they thrive in environments with clean air.
4. Option: Trees are very healthy — While lichen presence does not harm trees, it does not directly indicate the health of the trees themselves; rather, it reflects the air quality around the trees.

Thus, the best indicator of an unpolluted environment in the context of this question is the option that the location is not polluted.