Prior to the twentieth century, what were the leading causes of death?

• A. Infectious diseases
• B. Chronic diseases
• C. Accidents
• D. Malnutrition

Answer: (A)

The question tests how death patterns looked before modern medicine and public health changes. Before the twentieth century, infectious diseases were the main killers. Poor sanitation, crowded living conditions, lack of clean water, and no effective vaccines or antibiotics meant illnesses like tuberculosis, pneumonia, smallpox, cholera, and malaria caused far more deaths than other problems. As public health measures improved and medical advances like vaccines and antibiotics reduced deaths from infections, the pattern shifted and chronic conditions such as heart disease and cancer became the leading causes of death in many populations. Accidents and malnutrition were important health concerns, but they did not dominate mortality to the extent infectious diseases did in that era.