EVERYDAY SCIENCE

Detailed explanation-1: -It is present on the beaks, claws, and spurs. They are found mainly on the toes and metatarsus but may be found further up on the ankle in some birds. Thus evidence for the reptilian origin of birds is the occurrence of scales. Therefore, this is the correct option.

Detailed explanation-2: -Birds are the only living descendants of one of the major clades of theropod dinosaurs.

Detailed explanation-3: -Birds evolved from a group of meat-eating dinosaurs called theropods. That’s the same group that Tyrannosaurus rex belonged to, although birds evolved from small theropods, not huge ones like T. rex. The oldest bird fossils are about 150 million years old.

Detailed explanation-4: -Birds evolved from reptiles and are therefore seen as warm-blooded, feathered, flying reptiles. The most commonly held view is that theropod dinosaurs were ancestral to birds and modern flightless birds derived from these earlier flying birds.