Indicator of water pollution :

Options

A. E. Coli
B. Chlorella
C. Beggiatoa
D. Ulothrix

Answer

### Step-by-Step Solution:

1. **Understanding Water Pollution**: Water pollution refers to the contamination of water bodies (like rivers, lakes, and oceans) with harmful substances, which can include chemicals, waste, and pathogens. One major source of water pollution is fecal matter from sewage.

2. **Identifying Indicators of Water Pollution**: Indicators of water pollution are organisms or substances that signify the presence of contaminants in water. They help in assessing the quality of water and determining its safety for consumption.

3. **Role of E. coli**: E. coli (Escherichia coli) is a type of bacteria commonly found in the intestines of humans and animals. Its presence in water is a strong indicator of fecal contamination. Even a small percentage of fecal matter can render water unsafe for human consumption.

4. **Evaluating the Options**: The question likely provides multiple options. We need to identify which one is a recognized indicator of water pollution:
- **Option 1**: E. coli - This is a known indicator of fecal contamination.
- **Option 2**: Bigotia - This is a type of bacteria, but not specifically an indicator of fecal pollution.
- **Option 3**: Chlorella - This is a type of green algae, not an indicator of fecal pollution.
- **Option 4**: Eulothrix - This is also a filamentous algae, not related to fecal contamination.

5. **Conclusion**: Based on the analysis, the correct answer is **Option 1: E. coli**, as it is the primary indicator of fecal contamination in water.