Arrange the following groups of vertebrates in the order in which the…

The correct answer is Option (4) → B, D, A, C

NCERT traces the vertebrates in the order in which each group arose from the one before it. Fish came first, then animals that could live both on land and in water, then reptiles, and mammals came last.

B. Lobefins, fish with stout and strong fins — first. These fish could move on land and go back to water. The Coelacanth caught in South Africa belongs to this group.

D. The first amphibians, ancestors of frogs and salamanders — second. The lobefins evolved into the first amphibians, which lived on both land and water.

A. Reptiles that lay thick-shelled eggs — third. The amphibians evolved into reptiles. Their thick-shelled eggs do not dry up in the sun, unlike the eggs of amphibians.

C. The first mammals, which were like shrews — last. Mammals took over the earth when the reptiles came down.

So the correct order is B, D, A, C.

NCERT Extract:
A Brief Account of Evolution – “… Fish with stout and strong fins could move on land and go back to water. This was about 350 mya. In 1938, a fish caught in South Africa happened to be a Coelacanth which was thought to be extinct. These animals called lobefins evolved into the first amphibians that lived on both land and water. There are no specimens of these left with us. However, these were ancestors of modern day frogs and salamanders. The amphibians evolved into reptiles. They lay thick shelled eggs which do not dry up in sun unlike those of amphibians.”
A Brief Account of Evolution – “The first mammals were like shrews. Their fossils are small sized. Mammals were viviparous and protected their unborn young inside the mother’s body. Mammals were more intelligent in sensing and avoiding danger at least. When reptiles came down mammals took over this earth.”