The population pyramid: ● It is a graphical illustration that shows the distribution of various age groups in a population (typically that of a country or region of the world), which forms the shape of a pyramid when the population is growing. ● It is also used in ecology to determine the overall age distribution of a population ; an indication of the reproductive capabilities and likelihood of the continuation of a species. ● It mentions percentage-wise distribution within major age groups. ● Dependency ratio: It is an age-population ratio of those typically not in the labor force (less than 15, and more than 65) and those typically in the laborforce (15-65). So, option 1 is correct. ● The shape of the population pyramid indicates the birth rate and death rate . So, we can find whether the population is growing/stable or reducing. So, option 2 is correct. ● The population pyramid explicitly provides the percentages of males and females in all age groups . Thus, option 3 is also correct . ● Option 4 is NOT correct , as we cannot infer the size of the population. We can only find out its characteristics.