Why do scientists think that birds evolved from dinosaurs? a. some dinosaurs had feathers. b. birds and dinosaurs appeared on earth at approximately the same time. c. both are warm-blooded animals. d. birds and dinosaurs have more efficient hearts and lungs than mammals.

The correct answer is option A, Some dinosaurs had feathers

Explanation:

There were several evidences which could prove that birds evolved from dinosaur

a)Achaeopteryx which is a large-sized creature with toothed jaws, a long tail, and flight feathers has feather as a common feature between bird and them

b)Maniraptorans resembled lot many birds in the way that they have the similar shape of bones  

c)Some studies also said that the eggs of these dinosaurs were similar to the eggs of the bird

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