Treatement of polluted water is carried out with the help of

Options

A. Lichens
B. Fungi
C. Ferns
D. Phytoplankton.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks about the treatment of polluted water and the organisms that help in this process.

2. **Identifying the Nature of Polluted Water:**
Polluted water is often rich in organic matter that needs to be broken down to make the water cleaner and safer.

3. **Role of Decomposers:**
The treatment of polluted water typically involves decomposing microorganisms, which include fungi and bacteria. These organisms play a crucial role in breaking down organic matter into simpler, inorganic compounds.

4. **Biological Oxygen Demand (BOD):**
The breakdown of organic matter by these decomposers decreases the Biological Oxygen Demand (BOD) of the water, which is an important measure of water quality.

5. **Evaluating the Options:**
- **Lichens:** They are indicators of air pollution and do not treat water. Thus, this option is incorrect.
- **Fungi:** They are decomposers that help in breaking down organic matter in polluted water, making this option correct.
- **Ferns:** They do not play a significant role in the treatment of polluted water, so this option is incorrect.
- **Phytoplankton:** Similar to ferns, they do not contribute to the treatment of polluted water, making this option also incorrect.

6. **Conclusion:**
Based on the analysis of the options, the correct answer to the question is **B: Fungi**.

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