Lichens are indicators of

Options

A. water pollution
B. air pollution
C. soil pollution
D. all of these

Answer

**Step-by-Step Solution:**

1. **Understanding Lichens**: Lichens are unique organisms that form a symbiotic relationship between two different living organisms: algae and fungi. In this relationship, algae are responsible for photosynthesis, producing food, while fungi provide structure and protection.

2. **Identifying the Dominant Partner**: In the symbiotic relationship, fungi are considered the dominant partner. This means that fungi rely on the food produced by algae for their sustenance.

3. **Sensitivity to Pollution**: Lichens are sensitive to environmental changes, particularly air quality. They are especially sensitive to sulfur dioxide (SO2), a harmful gas released from vehicles and industrial processes.

4. **Indicators of Air Quality**: Due to their sensitivity to sulfur dioxide, lichens serve as bioindicators of air pollution. In areas with high levels of air pollution, particularly from sulfur dioxide, lichens struggle to survive and grow.

5. **Conclusion**: Therefore, the presence or absence of lichens in a particular area can indicate the level of air pollution. If lichens are thriving, it suggests that the air quality is good, while their absence indicates poor air quality.

**Final Answer**: Lichens are indicators of air pollution.

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