Q.An age pyramid with a broad base and a narrow apex, showing a large proportion of pre-reproductive individuals, represents a population that is:
(A) Declining
(B) Stable
(C) Expanding
(D) Extinct

A broad base of pre-reproductive individuals tapering to a narrow apex of older individuals produces the roughly triangular shape characteristic of an expanding population's age pyramid — a large fraction of individuals have not yet entered their reproductive years, so the population is set to keep growing as they mature and begin reproducing. A declining population (option A) instead shows an urn-shaped pyramid with a narrow base. A stable population (option B) shows a more even, bell-shaped distribution across the pre-reproductive and reproductive classes, not a broad base with a narrow apex. Option …

Memorise the shape-to-outcome mapping directly: triangular/broad base = expanding (growing); bell-shaped/eve …

Do not select "stable" just because a triangular shape looks orderly — stable pyramids specifically have roughly EQUAL proportions across age …