Which of the following is the most toxic excretory product?

Options

A. `CO_(2)`
B. Ammonia
C. Urea
D. Amino acids

Explanation

To determine which of the following is the most toxic excretory product among carbon dioxide, ammonia, urea, and amino acids, we can analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Excretory Products**:
- Excretory products are waste materials that are eliminated from the body. They can vary in toxicity levels.

2. **Analyzing Each Option**:
- **Carbon Dioxide (CO2)**:
- Produced during cellular respiration and is expelled through the lungs. While it can be harmful in high concentrations, it is not considered highly toxic in the context of excretion.

- **Ammonia (NH3)**:
- A byproduct of protein metabolism. It is highly toxic and can cause severe damage to cells and tissues. Aquatic animals, like fish, excrete ammonia directly into the water, where it is diluted. However, it requires a large amount of water for safe excretion.

- **Urea**:
- Less toxic than ammonia and is produced in the liver through the urea cycle. It is the primary nitrogenous waste in mammals and is excreted in urine. Urea is safer for storage and transport in the body compared to ammonia.

- **Amino Acids**:
- Building blocks of proteins and are not typically considered excretory products. They are utilized by the body for various functions and are not toxic.

3. **Conclusion**:
- Among the options provided, **ammonia** is the most toxic excretory product. It poses significant risks to organisms if not excreted quickly and efficiently.

### Final Answer:
**Ammonia is the most toxic excretory product.**

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