_______ protects lungs.

Options

A. Pleural membrane
B. Pleural fluid
C. Both (a) and (b)
D. Neither (a) nor (b)

Answer

**Step-by-Step Solution:**

1. **Identify the Options**: The question provides four options regarding what protects the lungs. The options are:
- A) Pleural membrane
- B) Pleural fluid
- C) Both A and B
- D) Neither A nor B

2. **Understand the Role of the Pleural Membrane**: The pleural membrane is a single membrane that surrounds each lung. It folds back on itself to form two layers, which provide a protective covering for the lungs.

3. **Understand the Role of the Pleural Fluid**: The pleural fluid is found in the pleural cavity, which is the space between the two layers of the pleural membrane. This fluid acts as a lubricant, allowing the lungs to expand and contract smoothly during breathing, and it also provides cushioning to protect the lungs.

4. **Conclusion**: Since both the pleural membrane and pleural fluid contribute to the protection of the lungs, the correct answer is that both A and B protect the lungs.

5. **Final Answer**: The correct answer is C) Both A and B.

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