Which term describes disease caused by bad air?

• A. Miasma
• B. Humour
• C. Germ theory
• D. Plague

Answer: (A)

Illness was historically linked to the quality of the air, and miasma is the term used for that idea. People believed a noxious vapor from decaying matter and foul-smelling air could cause disease simply by inhalation, so improving sanitation and removing putrid smells were seen as ways to prevent illness. This makes miasma the best fit for “disease caused by bad air.”

The other ideas describe different explanations: a humoral theory about imbalances of bodily fluids; germ theory, which attributes disease to microorganisms; and plague, which is a disease itself rather than a concept about its cause.