A significant contribution of Marx Women who have six or seven children tend to: belong exclusively to those developed countries of the world that have advanced technology. reside in urban, industrialized areas that have little access to birth control. live in agricultural regions of the world where children's labor is essential to the family's economic survival. live in countries where child mortality rates are very low.and Engels to the study of demography is the suggestion that __________. poverty, not overpopulation, is the central issue relating to food supply in a capitalist economy population grows exponentially but food supply grows arithmetically, thereby creating a doubling effect population explosion would eventually be checked by mortality risks, such as natural and man-made disasters the greatest crisis today facing low-income nations is food shortage, not capital shortage