Poland

This is a population pyramid of Poland. It is wide around 20-40. You can speculate that the country is developed because the pyramid shows their education. Countries with less education have many births, and countries that are developed and educate their citizens have pyramids that look like Poland's. The birth rate is under control, which can say a lot about a country, just from seeing how many children are born each year.

Kenya

This is a population pyramid of Kenya, and it is visible that it looks like an upside down "V". This is because there are more births than deaths, so there are many babies being born and it surpasses all of the adults in the country. You can speculate that the country has high birth rates because Kenya's women are having too many children which can be many things, like lack of birth control, or education about the subject.

Denmark

This is a population pyramid of Denmark. The population pyramid is wide at mid-ages (30-60) and not too far away from the children's width. You can speculate that the population is balanced and that yearly birth rates aren't out of control, if they were there would be more children. Or less yearly birth rates, which would make the pyramid wider on the top.