Define bronchitis.

• A. A viral infection of the pleura
• B. A respiratory infection causing difficult breathing
• C. A genetic disorder of the alveolar walls
• D. A chronic allergic reaction

Answer: (B)

Bronchitis is inflammation of the bronchial tubes, the airways that move air in and out of the lungs. When these passages become inflamed, they secrete more mucus and narrow, which makes breathing feel tougher and produces a cough, often with mucus. Acute bronchitis is usually caused by a viral infection, while chronic bronchitis is a long‑term inflammatory condition often linked to smoking. The other options describe conditions that don’t target the bronchi: inflammation of the pleura is pleuritis, a disease of the lining around the lungs; a genetic disorder of the alveolar walls points to problems with the air sacs themselves (like emphysema or fibrosis); a chronic allergic reaction resembles asthma more than bronchitis. The description that fits bronchitis best is a respiratory infection causing breathing difficulty.