Free Respiration MCQs with Answers

41. Which of the following is NOT caused by smoking?

• A. Malaria
• B. Lung cancer
• C. Emphysema
• D. Chronic bronchitis

Explanation: Malaria is transmitted by the Anopheles mosquito and has nothing to do with tobacco. Cancer, emphysema and chronic bronchitis form the classic trio of smoking diseases.

42. Babies born to mothers who smoke during pregnancy often have

• A. a higher than average birth weight
• B. a low birth weight
• C. extra ribs
• D. immunity against respiratory infection

Explanation: Carbon monoxide and nicotine reduce the oxygen and blood supply to the fetus, restricting growth and raising the risk of premature birth. This is one of the strongest arguments against smoking in pregnancy.

43. Damage to the cilia of the airways by smoking leads to

• A. improved filtering of dust
• B. faster removal of mucus
• C. accumulation of mucus and debris, producing the smoker's cough
• D. widening of the trachea

Explanation: Healthy cilia sweep mucus and trapped particles upwards, and when smoke paralyses them the debris collects instead. The cough is the body's substitute for the lost escalator.

44. Giving up smoking is particularly difficult mainly because

• A. tobacco is inexpensive
• B. cigarettes contain essential vitamins
• C. withdrawal produces no symptoms
• D. nicotine produces strong physical and psychological dependence

Explanation: Nicotine reaches the brain within seconds and alters reward pathways, so stopping brings cravings and withdrawal. Dependence, not price, is why most smokers need repeated attempts to quit.

45. The risk of lung cancer in a smoker rises with

• A. the brand of cigarette
• B. the time of day the cigarettes are smoked
• C. the length of the filter
• D. the number of cigarettes per day and the number of years of smoking

Explanation: Cancer risk follows cumulative dose: each cigarette adds exposure to carcinogens over years of tissue damage. No brand or filter makes the dose safe.

46. Smoking destroys the walls of the alveoli irreversibly, permanently reducing the respiratory surface. This disease is called

• A. emphysema
• B. asthma
• C. pneumonia
• D. bronchitis

Explanation: The merged, ragged air spaces of emphysema cannot transfer enough oxygen, leaving the patient breathless even at rest. Unlike bronchitis, the structural damage cannot be undone by drugs.

47. Which statement about hookah or shisha smoking is correct?

• A. It is safer than cigarettes because the smoke passes through water
• B. It also delivers nicotine, tar and carbon monoxide and is harmful
• C. It contains no tobacco at all
• D. It affects only the mouth

Explanation: The water cools the smoke but removes little tar or CO, and sessions are long, so intake is substantial. The belief that the water filters out harm is the myth this question tests.

48. The most effective way to reduce smoking related disease in a population is

• A. treating lung cancer at an earlier stage
• B. giving antibiotics to all smokers
• C. preventing people from starting and supporting smokers to quit
• D. switching smokers to cigars

Explanation: Emphysema and cancer are largely irreversible once established, so prevention and cessation save far more lives than treatment of late disease. Cigars carry the same tobacco harms.

49. The site of gas exchange in lungs is

• A. Bronchi
• B. Bronchioles
• C. Alveoli
• D. Trachea

Explanation: Alveoli are the site of gas exchange, with thin walls and large surface area for efficient O2 and CO2 diffusion.

50. Surfactant is produced by

• A. Type I alveolar cells
• B. Type II alveolar cells
• C. Goblet cells
• D. Ciliated cells

Explanation: Type II pneumocytes (alveolar cells) produce surfactant, which reduces surface tension to prevent alveolar collapse.