Correct option (d) frogs evolved from gilled ancestors
Explanation:
According to biogenetic law of Erhst Haeckel (1860) Ontogeny repeats Phylogeny. Ontogeny is the life history of an organism, while phylogeny is the evolutionary history of the race of that organism. In other words we can say an organism repeats its ancestral history during its development. Hence, resemblance of Amphibia to fish is seen in most systems of the body, both are cold-blooded, both respire by gills (as tadpole of frog), both usually lay eggs in water leading to the conclusion that amphibians have originated from fishes.
