Amphibians possess

Options

A. hepatic portal system
B. Renal portal system
C. hypophyseal portal system
D. all the above.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the systems that amphibians possess. We need to identify which circulatory systems are present in amphibians.

2. **Identifying the Types of Portal Systems**: There are several portal systems to consider:
- Hypophyseal portal system
- Hepatic portal system
- Renal portal system

3. **Hypophyseal Portal System**:
- This system is present in amphibians, reptiles, birds, and mammals.
- It involves the transport of hormones and deoxygenated blood from the hypothalamus to the anterior pituitary gland.

4. **Hepatic Portal System**:
- This system is responsible for transporting blood from the gastrointestinal tract and spleen to the liver.
- It is also present in amphibians.

5. **Renal Portal System**:
- This system transports blood from the lower parts of the body to the kidneys before it returns to the heart.
- It is well developed in amphibians, although less so in reptiles and birds, and absent in mammals.

6. **Conclusion**: Since amphibians possess all three systems (hypophyseal, hepatic, and renal portal systems), the correct answer is that amphibians possess these systems.

**Final Answer**: Amphibians possess the hypophyseal portal system, hepatic portal system, and renal portal system.

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