Final answer:
The first stage in moving from a developing to developed nation involves a transition where death rates decline due to public health improvements while birth rates remain high. This results in a period of high population growth known as Stage 2 of demographic transition.
Step-by-step explanation:
Demographic transition theory posits that the first stage in moving from a developing to a developed nation involves a significant decline in death rates due to improvements in public health measures, clean drinking water, and sanitation.
This change generally results in a high population growth rate. While birth rates remain high initially, due to traditional rural societies favoring larger families for agricultural labor, death rates fall more swiftly, leading to the demographic phenomenon described as Stage 2.
In this second stage, the population size escalates rapidly because although family size remains large, mortality rates have plummeted with advances in medicine and nutrition. Rural areas begin to urbanize, and income levels, while still low, begin to grow. Many individuals migrate to cities in search of better employment, which further fuels urbanization.
As a country continues to develop, it transitions into Stage 3, where birth rates start to fall, and a high rate of urbanization is observed. Eventually, the population's growth rates decrease and are expected to stabilize, leading to Stage 4, where both birth and death rates are low, and the population is stable. Stage 5 potentially sees a declining population in an urban, post-industrial society.