Question

give the evidence that birds evolved from reptiles

Answer 1

Archaeopteryx was a primitive bird that share many unique skeletal features with dinosaurs and we know that dinosaurs are reptiles. I think that this is the evidence that birds are evolved from reptiles.

Answer 2

The function of feathers initially was to provide insulation but later on they became useful for flight in birds only. Similarly, some dinosaurs had feathers, although they could not fly using the feathers. Birds seem to have later adapted the feathers to flight. This, of course, means that birds are very closely related to reptiles, since dinosaurs were reptiles.