The presence of 20 or more genera of algae in a water body is an indication of high organic pollution. It is

Options

A. Water index
B. Algal diversity index
C. Pollution index
D. Algal genus index

Answer

To solve the question regarding the presence of 20 or more genera of algae in a water body as an indication of high organic pollution, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**:
- The question states that the presence of 20 or more genera of algae in a water body indicates high organic pollution. We need to identify the term that describes this condition.

2. **Analyzing the Options**:
- The options provided are:
1. Water Index
2. Algal Diversity Index
3. Pollution Index
4. Algal Genus Index

3. **Evaluating Each Option**:
- **Water Index**: This index is used to monitor changes related to the water content in water bodies. It does not specifically relate to algal populations or organic pollution. Therefore, this option is incorrect.

- **Algal Diversity Index**: This index measures the richness of algal species in a water body. While it relates to algal populations, it does not specifically indicate organic pollution. Hence, this option is also incorrect.

- **Pollution Index**: This index measures air quality on a daily basis and does not pertain to algal presence or water quality related to organic pollution. Thus, this option is incorrect as well.

- **Algal Genus Index**: This index is specifically used to assess the different genera of algae present in water bodies. It is directly related to determining organic pollution levels in water samples. Therefore, this option is correct.

4. **Conclusion**:
- Based on the evaluation, the correct term that indicates high organic pollution when 20 or more genera of algae are present in a water body is the **Algal Genus Index**.

### Final Answer:
The presence of 20 or more genera of algae in a water body is an indication of high organic pollution, and the correct term for this condition is the **Algal Genus Index**.

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