Excretory products of fishes are:

Options

A. Ammonia
B. Urea
C. TMO
D. All of these

Answer

### Step-by-Step Solution:

1. **Understanding Excretory Products**: The excretory products in animals are substances that are eliminated from the body as waste. In fishes, these products primarily consist of nitrogenous wastes.

2. **Ammonia as an Excretory Product**:
- Fishes primarily excrete ammonia, which is a product of protein metabolism.
- Ammonia is highly toxic but is very soluble in water, making it easier for aquatic animals like fishes to excrete it directly into their surrounding environment.
- Examples of fishes that excrete ammonia include common carp and lampreys.

3. **Urea as an Excretory Product**:
- Some fishes convert nitrogenous waste into urea, which is less toxic than ammonia and can be stored in higher concentrations.
- Urea is excreted by certain species, such as Tilapia, which allows them to survive in environments where ammonia would be too toxic.

4. **Trimethylamine N-Oxide (TMAO)**:
- TMAO is another excretory product found in some marine fishes.
- It helps to stabilize proteins against the effects of high pressure in deep-sea environments.
- Marine fishes like sharks, cod, and squid utilize TMAO as part of their excretory process.

5. **Conclusion**:
- The main excretory products of fishes include ammonia, urea, and TMAO.
- Different species of fishes may utilize different excretory products based on their habitat and physiological adaptations.

### Final Answer:
The excretory products of fishes are ammonia, urea, and trimethylamine N-oxide (TMAO).

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