Two sided vertical bar graphs captioned 'Age-Structure Diagrams' is plotted between 'Population (in millions)' in x-axis ranging from 0 to 12 in increment of 2 and 'Age (years)' in y-axis ranging from 1 to 85 in a group of 5. Left and right side bars are marked as 'Male' and 'Female' respectively. Two graphs illustrates:

1. In United States - There are nearly equal numbers of people in each age group.
2. In Guatemala - As the age increases the population gradually decreases.