High value of BOD (Biochemical Oxygen Demand) indicates that:

Options

A. water is highly polluted
B. water is less polluted
C. consumption of organic matter in the water is higher by the microbes.
D. water is pure

Answer

To determine what a high value of BOD (Biochemical Oxygen Demand) indicates, we can follow these steps:

### Step-by-Step Solution:

1. **Understand BOD**: BOD measures the amount of oxygen that microorganisms will consume while decomposing organic matter in water. It is an important indicator of water quality.

2. **Interpret High BOD Value**: A high BOD value signifies that there is a large amount of organic matter present in the water. This means that microorganisms are consuming more oxygen to break down this organic matter.

3. **Link BOD to Pollution**: Since a high BOD indicates that a lot of oxygen is being consumed by bacteria to decompose organic waste, it suggests that the water is heavily polluted with organic materials.

4. **Evaluate the Options**:
- **Option 1**: Water is highly polluted - This aligns with our understanding of high BOD.
- **Option 2**: Water is less polluted - This contradicts the definition of high BOD.
- **Option 3**: Consumption of organic matter in the water is higher by microbes - While this is true, it does not directly answer the question about pollution levels.
- **Option 4**: Water is pure - This is the opposite of what high BOD indicates.

5. **Conclusion**: Based on the analysis, the correct answer is that a high value of BOD indicates that the water is highly polluted.

### Final Answer:
The correct answer is: **Water is highly polluted.**