High BOD indicates

Options

A. Highly polluted water
B. Less pollution in `H_(2)O`
C. Less sewage
D. Less microorganism

Answer

**Step-by-Step Solution:**

1. **Understanding BOD**: Begin by defining Biological Oxygen Demand (BOD). BOD is a measure of the amount of oxygen that microorganisms will consume while decomposing organic matter in water.

2. **Relation to Organic Matter**: Explain that a high BOD indicates a large concentration of organic matter in the water. This organic matter can come from various sources, such as sewage, agricultural runoff, or industrial waste.

3. **Microbial Activity**: Discuss how the presence of high organic matter activates decomposing bacteria. These microorganisms break down the organic material, which leads to an increased demand for dissolved oxygen in the water.

4. **Oxygen Consumption**: Clarify that as the bacteria decompose the organic matter, they consume dissolved oxygen. The more organic matter present, the higher the demand for oxygen, resulting in a higher BOD.

5. **Impact on Aquatic Life**: Highlight the consequences of high BOD on aquatic ecosystems. A significant decrease in dissolved oxygen levels can lead to the death of aquatic animals, as they rely on oxygen for survival.

6. **Conclusion**: Conclude that high BOD is indicative of highly polluted water. Therefore, the correct answer to the question is that high BOD indicates highly polluted water.

**Final Answer**: High BOD indicates highly polluted water.

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