Mark the odd one w.r.t. humus

Options

A. Slightly acidic
B. Colloidal in nature
C. Undergoes decomposition at every fast rate
D. Serves as a reservoir of nutrients

Answer

### Step-by-Step Solution:

1. **Understanding Humus**:
- Humus is a dark brown, amorphous, gummy substance formed from the partial decomposition of plant and animal matter. It is rich in organic components, particularly lignin and cellulose.

2. **Characteristics of Humus**:
- **Slightly Acidic**: Humus is known to be slightly acidic in nature due to the organic acids produced during decomposition.
- **Colloidal Nature**: It has a colloidal structure, which means it can hold moisture and nutrients effectively.
- **Nutrient Reservoir**: Humus acts as a reservoir for nutrients, slowly releasing them as it decomposes.

3. **Decomposition Rate**:
- The statement "undergoes decomposition at every fast rate" is incorrect. Humus decomposes slowly, which is a key characteristic that distinguishes it from other organic materials.

4. **Conclusion**:
- Based on the characteristics of humus, the odd one out with respect to humus is the statement that it "undergoes decomposition at every fast rate."

### Final Answer:
The odd one with respect to humus is: **"undergoes decomposition at every fast rate."**

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