What does fertility primarily measure in human populations?

Fertility primarily measures the potential for reproduction within human populations. It refers to the ability of individuals or couples to conceive and bear children, and is typically represented through metrics such as birth rates or total fertility rates. These measurements provide insights into how many children women are having within a specific period and can reflect broader socio-economic and cultural factors impacting family size and reproductive behavior.

Understanding fertility is critical in demographic studies, as it directly influences population structure and trends. It can help explain how populations grow or decline over time and is associated with various factors like health care access, education levels, and socio-economic conditions.

The other options focus on different aspects of population dynamics, such as mortality rates, which assess how many individuals die within a population; life expectancy, which indicates the average duration a person is expected to live based on demographic factors; and population growth, which is a broader concept reflecting the increase in the number of individuals in a population. While these factors interrelate, fertility specifically deals with the aspects of birth and reproduction.