Final answer:
The age-structure diagram for rapidly growing populations is in the form of a pyramid with a broad base indicating a large number of young individuals.
Step-by-step explanation:
The age-structure diagram for rapidly growing populations is in the form of a pyramid with a very broad base indicating a large number of young individuals. This means that there is a high proportion of young people in the population. The pyramid shape shows that the population has a high birth rate and a lower life expectancy, which is often observed in underdeveloped countries.