Final answer:
Population growth is fastest during the transitional stage of the Demographic Transition Model, where death rates fall significantly while birth rates remain high.
Step-by-step explanation:
In the context of the Demographic Transition Model (DTM), the question asks at which stage of the model population growth is the fastest. The DTM is a multistage model that describes the evolution from higher birth and death rates in pre-industrial societies to lower rates in post-industrial societies. During the transitional stage, often referred to as stage two, population growth is at its fastest. This surge is due to a rapid decline in death rates, resulting from medical, technological, and societal advances, while birth rates remain high. This creates a substantial net gain in population, often termed a 'population explosion.'
It's critical to recognize that the DTM is an idealized representation and that variations can occur based on cultural, economic, and historical factors. However, it's been a useful model in understanding population growth patterns as societies industrialize.