Even when there is no air in it, human trachea does not collapse due to the presence of :

Options

A. cartilaginous rings
B. chitinous rings
C. bony rings
D. turgid pressure

Explanation

**Step-by-Step Solution:**

1. **Understanding the Structure of the Trachea**: The trachea, also known as the windpipe, is a crucial part of the human respiratory system. It serves as a passage for air to travel to and from the lungs.

2. **Function of the Trachea**: The primary function of the trachea is to conduct air to the lungs where gaseous exchange occurs. It ensures that the air rich in oxygen reaches the alveoli, the site of gas exchange.

3. **Presence of Cartilaginous Rings**: The trachea is supported by a series of C-shaped cartilaginous rings. These rings are made of cartilage, which is a flexible yet strong connective tissue.

4. **Why the Trachea Doesn't Collapse**: Even when there is no air in the trachea, the presence of these incomplete cartilaginous rings prevents the trachea from collapsing. They provide structural support and maintain the shape of the trachea.

5. **Conclusion**: Therefore, the reason the human trachea does not collapse even when it is empty is due to the presence of these cartilaginous rings.

**Final Answer**: The human trachea does not collapse due to the presence of incomplete cartilaginous rings.

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