Which of the following are the indicators of pollution?

Options

A. Lichens
B. Fungi
C. Algae
D. None of these

Answer

To determine the indicators of pollution among the given options (lichens, fungi, algae, or none of these), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of Lichens**:
- Lichens are organisms formed from a symbiotic relationship between fungi and algae. They are known to be very sensitive to air quality, particularly to pollutants such as sulfur dioxide.

2. **Identify the Sensitivity of Lichens**:
- Lichens are particularly sensitive to air pollution. When there are high levels of sulfur dioxide in the air, lichens tend to die off. This makes them reliable indicators of air quality.

3. **Consider Other Options**:
- **Fungi**: While fungi play important roles in ecosystems, such as decomposing organic matter and forming symbiotic relationships with plants, they are not indicators of air pollution.
- **Algae**: Algae are primarily associated with water bodies and are more relevant in discussions about water quality and nutrient levels rather than air pollution. They are involved in processes like nitrogen fixation and are not sensitive indicators of air pollution.
- **None of These**: This option suggests that none of the listed organisms are indicators of pollution, which is incorrect since lichens are recognized as such.

4. **Conclusion**:
- Based on the sensitivity of lichens to sulfur dioxide and their decline in polluted environments, we conclude that lichens are the correct indicators of air pollution.

### Final Answer:
- **Lichens** are the indicators of pollution.

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