products of proteins catabolism are

Options

A. `NH_(3) ,CO_(2) and ` uera
B. Urea ,`CO_(2) and NH`
C. Urea `,NH_(3) and ` uric acid
D. Urea ,`NH_(3)` alanine and creatine

Answer

### Step-by-Step Solution:

1. **Understanding Protein Catabolism**:
- Protein catabolism refers to the process of breaking down proteins into smaller units. This process is essential for digestion and occurs in the body to utilize proteins for energy or other functions.

2. **Initial Breakdown**:
- The breakdown of proteins begins with enzymes such as pepsin, which is found in the stomach. Pepsin converts proteins into smaller chains called polypeptides.

3. **Further Degradation**:
- The polypeptides are further degraded into amino acids through the action of various enzymes in the digestive system.

4. **End Products of Protein Catabolism**:
- The catabolism of proteins leads to the formation of several end products:
- **Carbon Dioxide (CO2)**: A byproduct of cellular respiration.
- **Ammonia (NH3)**: A toxic compound that is produced during the breakdown of amino acids.
- **Urea**: Formed from ammonia in terrestrial animals to reduce toxicity and conserve water.

5. **Excretion in Different Organisms**:
- In aquatic animals, ammonia is excreted directly into the water due to its high solubility and the abundance of water around them.
- In terrestrial animals, ammonia is converted into urea to minimize water loss.
- Birds and some reptiles convert ammonia into uric acid, which is less toxic and conserves even more water.

6. **Final Conclusion**:
- Therefore, the primary products of protein catabolism are **carbon dioxide, ammonia, and urea**.