The correct option is (c).
Explanation
Smoking introduces harmful substances, including nicotine, tar, and carbon monoxide, into the respiratory system. These substances cause chronic inflammation and structural damage to lung tissues, leading to severe respiratory disorders and systemic health issues.
- Statement 1 is Incorrect: Smoking damages the walls of the alveoli (air sacs), leading to a condition known as emphysema. This damage reduces the respiratory surface area available for gas exchange, thereby significantly decreasing, rather than improving, the efficiency of the lungs.
- Statement 2 is Correct: Tobacco smoke contains numerous chemical carcinogens (cancer-causing agents). There is a scientifically established strong causal link between smoking and the development of lung cancer.
- Statement 3 is Correct: Chronic smoking leads to inflammation, scarring, and the destruction of lung tissue. This results in a loss of elasticity in the lungs and a reduction in vital capacity (the maximum amount of air a person can expel from the lungs after a maximum inhalation). Consequently, the lungs' ability to hold and exchange air is diminished.
Key Takeaway: Smoking is a major cause of respiratory disorders such as emphysema, chronic bronchitis, and lung cancer, all of which impair lung function and gas exchange efficiency.