1. Explain why these graphs are histograms by describing the variable on the y axis, units used, what the markings are for, and what is being measured on the x axis. Note that these density population graphs are standing on end, and each one is two graphs side by side (one for males and one for females) sharing the same x axis. 2. Describe the shape, center, and spread of the U.S. population's age in 1970 and then in 2020. 3. What story does each graph tell you about age distribution in 1970 and 2020? 4. What social, medical, and public health changes have occurred in the last 50 years to explain the difference in the age distribution of the United States?

Both graphs can be viewed online at the following website: https://population.un.org/wpp/Graphs/DemographicProfiles/Pyramid/840