Question

which of the following conclusions is supported by this diagram?
the birth rate has decreased during the past 10 years.
approximately the same number of boys as girls were born in the past 20 years.
the country experienced a population \boom\ 35 years ago.
there are nearly twice as many 70 - year - old men in the country as there are 70 - year - old women.

Explanation:

1. Analyze the first option: The diagram is a population pyramid (age - sex structure), and there is no time - series data about birth rate over the past 10 years. So we can't conclude the birth rate change from this diagram.
2. Analyze the second option: For the past 20 years, the youngest age groups (0 - 20 years old approximately) have different bar lengths (blue for males, red for females) in the diagram, so the number of boys and girls born in the past 20 years is not approximately the same.
3. Analyze the third option: Looking at the age group around 35 years old (since the current age of people born 35 years ago would be 35), the bar lengths (population) for that age group are relatively long, indicating a larger number of people born at that time, which is consistent with a population “boom” 35 years ago.
4. Analyze the fourth option: For 70 - year - old men and women, the bar length for 70 - year - old men (blue) is shorter than that for 70 - year - old women (red) in the diagram, so there are not nearly twice as many 70 - year - old men as women.

Answer:

The country experienced a population "boom" 35 years ago.