EVERYDAY SCIENCE

Detailed explanation-1: -Birds (class Aves) share a common ancestor with crocodiles in subclass Archosauria and are technically one lineage of reptiles, but they are treated separately (see bird).

Detailed explanation-2: -Complete answer: The fossil Archaeopteryx is the connecting link between the reptiles and birds. It looks like birds but has many other features like reptiles. It was a flightless bird which shows the characters of both reptiles and birds.

Detailed explanation-3: -The presence of homologous organs suggests that reptiles and birds share a common ancestor. The forelimbs of birds and reptiles have the same structure but they perform different functions and hence homologous organs. The forelimbs of reptiles are used for crawling, while, the forelimbs of birds are used for flying.

Detailed explanation-4: -Archaeopteryx has featured wings like birds but teeth and tail like those of reptiles. Therefore Archaeopteryx is a connecting link between the reptiles and birds and hence suggests that the birds have evolved from the reptiles.