The figure shows three age pyramids, A, B and C, of human populations…

The correct answer is Option (2) → A - Stable, B - Expanding, C - Declining

An age pyramid is drawn by plotting the per cent of individuals in each age group (pre-reproductive, reproductive and post-reproductive). Its shape shows whether the population is growing, stable or declining.

A — Stable. The pre-reproductive and reproductive bands are almost the same width, with the sides narrowing only near the top. Young individuals just replace the adults, so the size stays about the same.

B — Expanding. The pre-reproductive band is the widest, and each band above it is narrower. A large young population will soon enter the reproductive age, so the population grows.

C — Declining. The pre-reproductive band is narrower than the reproductive band above it. Fewer young are coming up to replace the adults, so the population shrinks.

Note: Three little pyramids with their names rubbed off make a full question. Figures in NCERT are not decoration, so study every one as closely as the text beside it.

NCERT Extract:
Population Attributes – “… A population at any given time is composed of individuals of different ages. If the age distribution (per cent individuals of a given age or age group) is plotted for the population, the resulting structure is called an age pyramid (Figure 11.1). For human population, the age pyramids generally show age distribution of males and females in a diagram. The shape of the pyramids reflects the growth status of the population - (a) whether it is growing, (b) stable or (c) declining.”

Figure 11.1 Representation of age pyramids for human population