The foul smell of faeces is due to

Options

A. Skatol, Indole
B. Annnonia
C. Small and large intestine
D. Methyl mercaptan

Answer

### Step-by-Step Solution:

1. **Understanding the Components of Feces**: Feces are composed of various substances, including undigested food, bacteria, and waste products from the body.

2. **Identifying the Source of Odor**: The foul smell of feces is primarily due to the presence of certain organic compounds produced during digestion.

3. **Key Compounds Responsible for Odor**: The two main compounds that contribute to the foul smell are:
- **Scatol**: A compound formed from the breakdown of tryptophan.
- **Indole**: Another compound that is also derived from the microbial degradation of tryptophan.

4. **Role of Microbial Activity**: The human intestine hosts a variety of bacteria that play a crucial role in breaking down food substances. During this process, tryptophan, an amino acid found in many proteins, is metabolized by these bacteria, leading to the formation of scatol and indole.

5. **Conclusion**: Therefore, the foul smell of feces is primarily due to the presence of scatol and indole, which are products of the microbial degradation of tryptophan in the intestine.

### Final Answer:
The foul smell of feces is due to scatol and indole.

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