UPSC Prelims 2009 · General Studies

Question 149: Science and Technology

With reference to the evolution of living organisms, which one of the following sequences is correct?

aOctopus – Dolphin – Shark

bPangolin – Tortoise – Hawk

cSalamander – Python – Kangaroo

dFrog – Crab – Prawn

AnswerThe answer is (c).

Evolution produced amphibians, then reptiles, then mammals. Salamander (amphibian), python (reptile) and kangaroo (mammal) follow that order. The other sequences break it: Octopus, Dolphin, Shark puts a mammal before a fish; Pangolin, Tortoise, Hawk puts a mammal before a reptile; Frog, Crab, Prawn puts a vertebrate before invertebrates.

Why each option is right or wrong

(a) Wrong: the dolphin (a mammal) evolved after the shark (a fish).
(b) Wrong: the pangolin (a mammal) evolved after the tortoise (a reptile).
(c) Right: amphibian, then reptile, then mammal.
(d) Wrong: crab and prawn are invertebrates, which came before the frog.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2009, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.