Final answer:
In Stage 2 of the Demographic Transition, one reason for the declining death rates is the improvement in healthcare and sanitation as countries begin to industrialize.
Step-by-step explanation:
In Stage 2 of the Demographic Transition, birth rates are higher while death rates drop. One reason for this decline in death rates is the improvement in healthcare and sanitation as countries begin to industrialize. With advancements in medicine and access to clean water, people are able to live longer, resulting in a decrease in death rates.