Which of the following statements is correct?

Options

A. The ascending limb of loop of Henle is impermeable to water.
B. The descending limb of loop of Henle is impermeable to water.
C. The ascending limb of loop of Henle is permeable to water.
D. The descending limb of loop of Henle is permeable to electrolytes

Answer

To determine which statement is correct regarding the loop of Henle, we can analyze each statement step by step.

### Step-by-Step Solution:

1. **Understand the Structure of the Loop of Henle**:
- The loop of Henle consists of two limbs: the descending limb and the ascending limb.
- The descending limb is responsible for the reabsorption of water, while the ascending limb is involved in the reabsorption of electrolytes.

2. **Evaluate the First Statement**:
- **Statement**: "The ascending limb of loop of Henle is impermeable to water."
- **Analysis**: This statement is correct. The ascending limb does not allow water to pass through, making it impermeable to water.

3. **Evaluate the Second Statement**:
- **Statement**: "The descending limb of loop of Henle is impermeable to water."
- **Analysis**: This statement is incorrect. The descending limb is permeable to water, allowing water to be reabsorbed.

4. **Evaluate the Third Statement**:
- **Statement**: "The ascending limb of loop of Henle is permeable to water."
- **Analysis**: This statement is also incorrect. As mentioned earlier, the ascending limb is impermeable to water.

5. **Evaluate the Fourth Statement**:
- **Statement**: "The descending limb of loop of Henle is permeable to electrolytes."
- **Analysis**: This statement is incorrect. The descending limb is impermeable to electrolytes.

6. **Conclusion**:
- After evaluating all the statements, the only correct statement is the first one: "The ascending limb of loop of Henle is impermeable to water."

### Final Answer:
The correct statement is: **The ascending limb of loop of Henle is impermeable to water.**

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