Aprimary difference between the age pyramids of industrialized and developing countries is that: choose the correct answer from the following choices, and then select the submit answer button. developing countries show a characteristic "bulge" that indicates a baby boom. in developing countries, much larger proportions of the population are in the youngest age groups. mean longevity is significantly greater in developing countries. in developing countries, females live significantly longer than males, whereas the reverse is true in industrialized countries. developing countries have significantly more individuals than industrialized countries.