Final answer:
A country likely moves from Stage 1 to Stage 2 in the DTM due to advancements in medicine, nutrition, and sanitation, which lower death rates and lead to high population growth.
Step-by-step explanation:
The likely reason a country would move from Stage 1 to Stage 2 in the Demographic Transition Model (DTM) is greatly improved medical practices which allow people to live longer, healthier lives. In Stage 2, advancements in nutrition, sanitation, and medicine lead to a sharp decline in death rates, particularly infant mortality, while birth rates remain high due to cultural traditions that encourage larger family sizes. This combination results in a high population growth rate. Countries in Stage 2 are typically experiencing urbanization and are beginning to integrate economically with the outside world.