Lichens are very sensitive to :

Options

A. `O_(2)`
B. `CO_(2)`
C. `N_(2)`
D. `SO_(2)`

Answer

**Step-by-Step Solution:**

1. **Understanding Lichens**: Lichens are symbiotic organisms composed of fungi and algae or cyanobacteria. They are known for their sensitivity to environmental changes, particularly air quality.

2. **Identifying the Options**: The question provides four gases: oxygen, carbon dioxide, nitrogen (N2), and sulfur dioxide. We need to determine which of these gases lichens are particularly sensitive to.

3. **Analyzing Sensitivity**: Lichens are known to be bioindicators, meaning they can indicate the quality of the environment. They are especially sensitive to pollutants in the air.

4. **Focusing on Sulfur Dioxide**: Among the options given, sulfur dioxide (SO2) is a known air pollutant that can have detrimental effects on lichens. High levels of sulfur dioxide can lead to the rapid accumulation of sulfur in lichens, which can be harmful.

5. **Conclusion**: Based on the analysis, lichens are very sensitive to sulfur dioxide, making option D the correct answer.

**Final Answer**: Lichens are very sensitive to sulfur dioxide (SO2).

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