Measure of __________, gives the estimate amount of biodegradable organic matter in sewage water.

Options

A. Biomagnification
B. BOD
C. SPM
D. all except (2)

Answer

To answer the question "Measure of __________, gives the estimate amount of biodegradable organic matter in sewage water," we need to fill in the blank with the correct term that relates to the assessment of organic matter in sewage.

### Step-by-Step Solution:

1. **Understanding Organic Matter**: Organic matter in sewage water primarily consists of biodegradable waste, which includes substances like food scraps, human waste, and other organic materials that bacteria can decompose.

**Hint**: Think about what types of waste are present in sewage and how they can be broken down.

2. **Role of Bacteria**: Bacteria play a crucial role in breaking down this organic matter. They require oxygen to survive and to perform the decomposition process effectively.

**Hint**: Consider the relationship between bacteria and oxygen in the context of waste decomposition.

3. **Oxygen Demand**: The amount of oxygen required by bacteria to decompose organic matter in water is referred to as Biochemical Oxygen Demand (BOD). A higher BOD indicates a greater amount of biodegradable organic matter present in the sewage.

**Hint**: Recall the term that quantifies the oxygen needed for bacterial activity in water.

4. **Interpreting BOD Values**: If the BOD is high, it means there is a lot of organic waste, indicating that the water is more polluted. Conversely, a lower BOD suggests less organic matter and therefore cleaner water.

**Hint**: Think about how BOD values can indicate the level of pollution in water.

5. **Final Answer**: Therefore, the correct term to fill in the blank is "BOD" (Biochemical Oxygen Demand).

### Final Answer:
Measure of **BOD**, gives the estimate amount of biodegradable organic matter in sewage water.