Pollution indicator plants

Options

A. Are resistant to pollution
B. Can purify the atmosphere
C. Are very sensitive to pollutants
D. Can indicate onset of rains.

Answer

### Step-by-Step Solution:

1. **Understanding Pollution Indicator Plants**:
- Pollution indicator plants are species that can provide information about the level of pollution in an environment. They respond to changes in environmental conditions, particularly pollution levels.

2. **Identifying Characteristics**:
- These plants are characterized by their sensitivity to pollutants. When pollution levels rise, these plants often show signs of stress or decline in health.

3. **Examples of Pollution Indicator Plants**:
- A common example is lichens, which are sensitive to air quality, particularly to sulfur dioxide. When air pollution increases, the population of lichens in that area decreases.

4. **Analyzing the Options**:
- Option A: "Are resistant to the pollution" - This is incorrect as pollution indicator plants are not resistant; they are sensitive.
- Option B: "Can purify the atmosphere" - While some plants can help improve air quality, this does not define pollution indicator plants.
- Option C: "Are very sensitive to the pollutants" - This is correct, as these plants indicate pollution levels by their presence or absence.
- Option D: "Can indicate onset of the rains" - This is unrelated to pollution.

5. **Conclusion**:
- Based on the characteristics and examples discussed, the correct answer is **Option C: are very sensitive to the pollutants**.