The lung is enclosed in a double layered membrane called :

Options

A. pericardium
B. pleura
C. periosteum
D. perichondrium

Explanation

**Step-by-Step Solution:**

1. **Understanding the Structure of the Lungs:**
- The lungs are essential organs in the respiratory system responsible for gas exchange, allowing oxygen to enter the bloodstream and carbon dioxide to be expelled.

2. **Location of the Lungs:**
- The lungs are located in the thoracic cavity (chest cavity) and are surrounded by a protective structure.

3. **Identifying the Protective Membrane:**
- The lungs are enclosed in a double-layered membrane that provides structural support and reduces friction during breathing movements.

4. **Naming the Membrane:**
- This double-layered membrane is known as the **pleura**. It consists of two layers:
- The **visceral pleura**, which is the inner layer that directly covers the lungs.
- The **parietal pleura**, which is the outer layer that lines the thoracic cavity.

5. **Function of the Pleura:**
- Between these two layers is a space filled with pleural fluid. This fluid serves several purposes:
- It reduces friction between the lungs and the thoracic wall during breathing.
- It acts as a cushion, protecting the lungs from injury.

6. **Conclusion:**
- Therefore, the correct answer to the question "The lung is enclosed in a double layered membrane called:" is **pleura**.

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