1. Age: The horizontal axis of the population pyramid typically represents age cohorts, with younger ages at the bottom and older ages at the top. This allows viewers to visualize the age distribution of the population, showing the proportion of individuals in different age groups.

2. Gender: Population pyramids often have two sides, one representing males and the other representing females. This allows for a comparison of the population structure between genders, showing the relative numbers of males and females in each age group.

3. Growth: Population pyramids can also indicate population growth trends. A pyramid with a wide base and narrower top suggests a growing population, as there are more young individuals than older ones. Conversely, a pyramid with a narrow base and broader top suggests a shrinking population, as there are fewer young individuals than older ones.

Therefore, the population pyramid typically shows age distribution, gender composition, and growth trends within a population, making it a valuable tool for understanding population dynamics.