Which of the following are highly sensitive to oxide of sulphur and are indicators of sulphur pollution ?

Options

A. Equisetum
B. Lichen
C. Eucalyptus
D. Eichhornia

Answer

To solve the question "Which of the following are highly sensitive to oxide of sulphur and are indicators of sulphur pollution?", we will follow these steps:

### Step 1: Understand the Question
The question asks for organisms that are sensitive to sulfur oxides and can indicate sulfur pollution. We need to identify which options fit this criterion.

### Step 2: Analyze the Options
We have several options to consider. We need to evaluate each one to see if they are known indicators of sulfur pollution.

1. **Lichens**: Known to be sensitive to air pollution, particularly sulfur dioxide. They are symbiotic organisms made up of fungi and algae. Their growth decreases in areas with high sulfur dioxide levels, making them reliable indicators of sulfur pollution.

2. **Euclidatum (Horsetail)**: This plant is not known to be sensitive to sulfur oxides and does not serve as an indicator of sulfur pollution.

3. **Eucalyptus**: While a significant tree species, eucalyptus is not specifically sensitive to sulfur oxides and does not indicate sulfur pollution.

4. **Echornia (Water Hyacinth)**: This is an invasive weed and is not recognized as an indicator of sulfur pollution.

### Step 3: Conclusion
Based on the analysis, the organism that is highly sensitive to oxides of sulfur and serves as an indicator of sulfur pollution is **Lichens**.

### Final Answer
The correct answer is **Lichens**.

---