in amphibians

Options

A. exoskeleton is absent
B. skin is respiratory
C. both A and B
D. none of the above

Answer

**Step-by-Step Solution:**

1. **Understanding Amphibians**: Amphibians are a class of animals that can live both in water and on land. They are characterized by their ability to undergo metamorphosis from a larval stage (usually aquatic) to an adult stage (usually terrestrial).

2. **Identifying Key Characteristics**:
- Amphibians have two pairs of limbs, making them tetrapods (four-limbed).
- They possess a moist skin that plays a crucial role in respiration.

3. **Exoskeleton in Amphibians**:
- An exoskeleton is an external skeleton that provides support and protection to the body. It is found in many organisms, such as insects and crustaceans.
- In amphibians, the exoskeleton is absent. Instead, they have a soft, permeable skin that allows for gas exchange.

4. **Skin Functionality**:
- The skin of amphibians is highly vascularized, meaning it has a rich supply of blood vessels. This structure facilitates the exchange of gases (oxygen and carbon dioxide) directly through the skin.
- Thus, the skin serves as a respiratory organ in addition to its protective role.

5. **Evaluating the Options**:
- Option A: "Exoskeleton is absent" - This is true for amphibians.
- Option B: "Skin is respiratory" - This is also true as the skin functions in respiration.
- Option C: "Both A and B" - Since both statements are correct, this option is also true.
- Option D: "None of the above" - This is incorrect because we have established that A and B are true.

6. **Conclusion**: The correct answer to the question is option C: "Both A and B".

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