Arrange the eukaryotic organisms given in global biodiversity according to their increasing number.
(A) Mammals
(B) Crustacea
(C) Insects
(D) Other animal groups
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (B), (A), (D), (C)
Note: The given answer is as per the official NTA Answer Key. However, none of the options is strictly correct. But mammals and crustaceans are drawn in two different pie charts (vertebrates and invertebrates). In real numbers mammals are far fewer than crustaceans, so the correct order is (A), (B), (D), (C), which is not among the options, as explained below.
NCERT shows global biodiversity in three pie charts: plants, invertebrates and vertebrates. Among animals, insects are the most species-rich group, making up more than 70 per cent of all animals. So insects come last in any increasing order.
(A) Mammals — a slice of the vertebrate pie. Vertebrates as a whole are a small part of all animals, so mammals are the smallest group here. NTA’s answer places them second because their slice looks larger than the thin crustacean slice.
(B) Crustacea — a thin slice of the invertebrate pie. But that pie holds most of the world’s animal species, so crustaceans are still more numerous than mammals. NTA’s answer places them first.
(D) Other animal groups — third. In the invertebrate pie this slice is larger than those of crustaceans and molluscs.
(C) Insects — last. Insects are the largest group of all.
NCERT Extract:
