The venous system of frog differs from that of rat in having

Options

A. Hepatic vein
B. Three vena cavae
C. Renal portal system
D. Hepatic portal system

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks how the venous system of frogs differs from that of rats. We need to identify a specific feature that is present in frogs but absent in rats.

2. **Analyzing the Options**: The options provided include various components of the venous system. We need to evaluate each option to determine its presence in frogs and rats.

3. **Evaluating the Vena Cava**: The vena cava is a major vein that carries deoxygenated blood from the body to the heart. Both frogs and rats possess a vena cava, so this option is incorrect.

4. **Considering the Renal Portal System**: The renal portal system is a unique feature found in frogs. This system allows deoxygenated blood from the lower body to be directed to the kidneys via the renal portal vein for filtration before returning to the heart. This system is absent in mammals, including rats.

5. **Checking the Hepatic Portal System**: The hepatic portal system is responsible for directing blood from the gastrointestinal tract to the liver. This system is present in both frogs and rats, making this option incorrect.

6. **Conclusion**: The venous system of frogs differs from that of rats in having the renal portal system. Therefore, the correct answer is that frogs possess a renal portal system, which is not found in rats.

**Final Answer**: The venous system of frogs differs from that of rats in having a renal portal system.

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