The population in the United States is growing even though fertility rates have dropped below the level needed to maintain the population level because

A) there has been a decrease in life expectancy.
B) the mortality rate is increasing.
C) there have been considerable advances in modern medicine.
D) immigration rates have risen.

Fertility Rates

Fertility rates describe the average number of children born to a woman over her lifetime within a population.

Modern Medicine

The practice of medicine based on the application of scientific knowledge, technology, and research to prevent, diagnose, and treat diseases.

Immigration Rates

The frequency or number of individuals moving into a country or region to live permanently, impacting the demographic composition.