Marine teleost fish excrete

Options

A. Ammonia
B. Urea
C. Uric acid
D. Amino acids

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the type of nitrogenous waste excreted by marine teleost fish.

2. **Identifying Nitrogenous Wastes**: There are three main types of nitrogenous wastes produced by animals: ammonia, urea, and uric acid. Each type is associated with different groups of organisms.

3. **Characteristics of Marine Teleost Fish**: Marine teleost fish are a specific group of bony fish that live in saltwater environments. Unlike many other aquatic organisms that primarily excrete ammonia, marine teleost fish have adapted to excrete urea.

4. **Ureotelic Nature**: Marine teleost fish are classified as ureotelic organisms, meaning they primarily excrete urea as their nitrogenous waste. This adaptation helps them conserve water in their marine environment, as urea is less toxic and requires less water for excretion compared to ammonia.

5. **Elimination of Other Options**:
- **Ammonia**: This is incorrect for marine teleost fish. Ammonia is typically excreted by many freshwater fish and is highly toxic.
- **Uric Acid**: This is incorrect as well. Uric acid is excreted by uricotelic organisms, such as reptiles and birds.
- **Amino Acids**: This is also incorrect. Organisms do not typically excrete amino acids directly; they are metabolized into other forms of nitrogenous waste.

6. **Conclusion**: Based on the information, the correct answer is that marine teleost fish excrete **urea**.

**Final Answer**: Marine teleost fish excrete **urea** as their nitrogenous waste.

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