BOD is in polluted water and _ in potable water.

Options

A. more, less
B. less, medium
C. medium, more
D. less, more

Answer

To solve the question "BOD is in polluted water and _ in potable water," we need to understand the concept of Biochemical Oxygen Demand (BOD) and its implications in different types of water.

### Step-by-Step Solution:

1. **Define BOD**:
- BOD stands for Biochemical Oxygen Demand. It measures the amount of oxygen that microorganisms will consume while decomposing organic matter in water.

2. **Understand the relationship between BOD and water quality**:
- In polluted water, there is a higher concentration of organic matter. This leads to an increased demand for oxygen by microorganisms, resulting in a higher BOD level.
- Conversely, in potable (drinking) water, the organic matter content is significantly lower, leading to a reduced demand for oxygen and thus a lower BOD.

3. **Compare BOD levels in polluted and potable water**:
- Since polluted water has more organic matter, it will have a higher BOD.
- Potable water, being clean and safe for drinking, will have a lower BOD due to the minimal presence of organic matter.

4. **Fill in the blanks**:
- Based on the understanding that BOD is higher in polluted water and lower in potable water, we can complete the statement: "BOD is in polluted water and **less** in potable water."

### Final Answer:
BOD is in polluted water and **less** in potable water.

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