Identify correct statements about age structure of population.

(A) Nigeria has triangular shaped age-sex pyramid.
(B) Australia's age-sex pyramid is bell shaped.
(C) Japan has a narrow base pyramid.
(D) Mexico has bell shaped age-sex pyramid.

Choose the correct answer from the options given below:

(A), (B) and (C) only

The correct answer is Option (3) → (A), (B) and (C) only

(A) Nigeria has triangular shaped age-sex pyramid – Correct. Nigeria, a developing country with high birth and death rates, has a triangular (expansive) pyramid shape, indicating a young population and rapid population growth.

(B) Australia's age-sex pyramid is bell shaped – Correct. Australia, a developed country with moderate birth and death rates, shows a bell-shaped pyramid, reflecting low population growth and balanced age distribution.

(C) Japan has a narrow base pyramid – Correct. Japan has a narrow base due to low birth rates, indicating an ageing population and a declining growth rate.

(D) Mexico has bell shaped age-sex pyramid – Incorrect. Mexico, being a developing country, has a pyramid closer to triangular in shape, showing higher birth rates and a younger population — not a bell shape.

Note: This question is from pre rationailsed NCERT.