Which factor has not contributed to a dramatic increase in the world's population in recent centuries?

A. Improved medical care

B. Decreasing death rates

C. Population clusters in cities

D. Modern farming techniques

Answer: C. Population clusters in cities

Increase in the world's population can be affected by improved medical care, decreasing death rates, and modern farming techniques. Thru improved medical care, there will be less death due to illnesses. Thru modern farming techniques, there will be no famine that is a cause of death also.

Population clusters in the cities will increase the population in the city but not the population in the world as a whole.