Major cause for the respiratory disorder, characterized by decreased respiratory surface area is

Options

A. Tobacco chewing
B. Hypersensitivity
C. Bacteria
D. Tobacco smoking

Answer

**Step-by-Step Solution:**

1. **Identify the Respiratory Disorder**: The question asks about a respiratory disorder characterized by decreased respiratory surface area. The disorder in question is likely emphysema.

2. **Understand Emphysema**: Emphysema is a lung condition where the walls of the alveoli (air sacs in the lungs) break down, leading to a decrease in the surface area available for gas exchange. This results in difficulty breathing and reduced oxygen supply to the body.

3. **Evaluate the Options**: The options provided are:
- Tobacco chewing
- Hypersensitivity
- Bacteria
- Tobacco smoking

4. **Analyze Each Option**:
- **Tobacco chewing**: While harmful, it primarily affects oral health and does not directly cause emphysema.
- **Hypersensitivity**: This refers to allergic reactions and does not directly lead to decreased respiratory surface area.
- **Bacteria**: While bacterial infections can lead to respiratory issues, they are not the primary cause of emphysema.
- **Tobacco smoking**: This is well-known to be a major cause of emphysema. Smoking damages the lung tissue, leading to inflammation and destruction of alveolar walls, which reduces the respiratory surface area.

5. **Conclusion**: Based on the analysis, the major cause for the respiratory disorder characterized by decreased respiratory surface area is **tobacco smoking**.

**Final Answer**: Tobacco smoking.

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