Which usually causes fibrosis in lungs ?

Options

A. Lead
B. Asbestoos
C. CFC
D. DDT

Answer

### Step-by-Step Solution:

1. **Understanding Pulmonary Fibrosis**:
- Pulmonary fibrosis is a type of interstitial lung disease characterized by scarring (fibrosis) of lung tissue. This scarring makes it difficult for the lungs to function properly.

2. **Identifying Causative Agents**:
- Various toxins can lead to pulmonary fibrosis. Common agents include asbestos, coal dust, and silica. These substances can cause damage to lung tissue when inhaled.

3. **Analyzing the Options**:
- The options provided are lead, asbestos, CFC (chlorofluorocarbons), and DDT (dichloro-diphenyl-trichloroethane).
- **Lead**: Primarily associated with heavy metal poisoning and not directly linked to lung fibrosis.
- **Asbestos**: Known to cause lung diseases, including pulmonary fibrosis, especially in workers exposed to it (e.g., construction workers, shipyard workers).
- **CFCs**: Mainly involved in ozone depletion and not directly linked to lung fibrosis.
- **DDT**: A pesticide that has been banned due to its environmental impact and does not cause lung fibrosis.

4. **Conclusion**:
- Among the given options, **asbestos** is the substance that usually causes fibrosis in the lungs.

### Final Answer:
**Asbestos usually causes fibrosis in the lungs.**

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