What is a population pyramid?

A population pyramid is a graphical representation of the age and sex distribution of a population, typically shown as two back-to-back bar graphs. Each bar represents the number of individuals within a specific age group, with males typically depicted on one side and females on the other. The shape of the pyramid can reveal crucial information about the demographic structure of a society, such as birth rates, mortality rates, and overall population growth or decline.

This format allows for easy visual assessment of trends, including the proportion of young versus old individuals, which can inform policymakers about potential needs for services such as education, healthcare, and employment. The pyramid's shape can vary; for example, a pyramid with a wide base indicates a high birth rate, while a more rectangular shape suggests low birth and death rates, typical of developed countries.

The other choices do not define a population pyramid accurately. Charts showing economic growth over time reflect economic data rather than demographic structures. Maps of population density illustrate how population is spread across an area rather than age and sex distribution. Models predicting future population trends use various demographic indicators but do not visually represent age and sex distribution in the way a population pyramid does.