The excretory matter of bony fish as :

Options

A. Urea
B. Protein
C. Ammonia
D. Amino acid

Answer

**Step-by-Step Solution:**

1. **Understanding Excretion in Bony Fish:**
- Bony fish primarily live in aquatic environments, which influences their method of excretion.

2. **Identifying the Main Excretory Product:**
- The main excretory product for bony fish is ammonia. This is due to its high solubility in water, allowing it to be easily excreted into their aquatic environment.

3. **Toxicity of Ammonia:**
- Although ammonia is toxic to living organisms, bony fish can afford to excrete it directly into the water because they are constantly surrounded by it, which dilutes its concentration.

4. **Comparison with Other Excretory Products:**
- Other animals, such as birds, reptiles, and insects, convert ammonia into urea or uric acid to reduce toxicity and conserve water. However, bony fish do not undergo this conversion.

5. **Conclusion:**
- Therefore, the correct answer to the question about the excretory matter of bony fish is ammonia.

**Final Answer:**
The excretory matter of bony fish is ammonia.

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