Lichens are very sensitive to________________ pollutant ?

Options

A. `CO`
B. `CO_(2)`
C. `NO_(x)`
D. `SO_(2)`

Answer

**Step-by-Step Solution:**

1. **Understanding Lichens**: Lichens are composite organisms formed by the symbiotic association of fungi and algae. The algae provide carbohydrates through photosynthesis, while the fungi offer protection and structure.

2. **Sensitivity of Lichens**: Lichens are known to be bioindicators of air quality. They are particularly sensitive to certain air pollutants, which can affect their growth and survival.

3. **Identifying the Pollutants**: The question provides a list of pollutants: carbon monoxide, carbon dioxide, nitrogen oxide, and sulfur dioxide. We need to determine which of these pollutants lichens are most sensitive to.

4. **Research on Lichens and Pollution**: Studies have shown that lichens are especially sensitive to sulfur dioxide (SO2) pollution. Areas with high levels of SO2 typically have fewer or no lichens.

5. **Conclusion**: Based on the sensitivity of lichens to sulfur dioxide, we conclude that lichens are very sensitive to sulfur dioxide pollution.

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

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