What underlying cause is primarily responsible for the observed decrease in birth rates as countries move through the later stages of the Demographic Transition Model?

The main reason for the decrease in birth rates as countries progress through the later stages of the Demographic Transition Model is the shift in social and economic conditions. As countries develop, people often prioritize education and careers, which leads to delayed marriage and childbearing. For example, in many advanced countries, women are encouraged to pursue higher education and jobs, which results in fewer children being born. Additionally, improved access to healthcare and family planning allows families to make informed choices about the number of children they want. This combination of changing values and better resources contributes to lower birth rates in developed nations.