Final answer:
Population pyramids use Age and Gender as statistical categories to graphically represent the age-sex structure of a population, providing insights into societal dynamics like economic development and social stability.
Step-by-step explanation:
Population pyramids use two statistical categories to represent demographic information: Age and Gender. These pyramids are powerful visual tools that graphically display the distribution of various age cohorts within a population for males and females, often depicted on the left and right sides of the pyramid, respectively. This information is crucial in understanding the demographic composition and can indicate aspects of population demands, such as potential for economic development, social stability, and political dynamics. For example, a 'youth bulge' may reflect a high number of young adults entering the labor force and electorate, which can have significant implications for a country.
Population pyramids can take various shapes, each paralleling a stage of a country's economic development. These shapes can vary from rapid growth with a broad base and narrow top to negative growth with a narrower base and broader top portions of the pyramid. Changes in population composition due to differing fertility, mortality, and migration rates further refine the demographic profile of a population, as illustrated by population pyramids.