What trend is tracked by the demographic transition theory, which addresses changing fertility and mortality rates over time?

A) an alarming increase in death rates in the developing countries
B) dramatically increasing fertility rates in the underdeveloped world
C) increasing birth and death rates in overurbanized cities worldwide
D) a movement from high to low birth and death rates in wealthier nations

Demographic Transition Theory

A theory that explains how countries move from high to low birth and death rates as they progress from pre-industrial to industrial economic systems.

Fertility Rates

The typical amount of children a woman gives birth to throughout her life in a given population.

Mortality Rates

A measure of the number of deaths in a given population, scaled to the size of that population, per unit of time.