EVERYDAY SCIENCE

Detailed explanation-1: -All the characteristics are shared by birds and mammals except viviparity. Birds are oviparous while mammals are oviparous (prototherians) and viviparous (metatherians and eutherians).

Detailed explanation-2: -The most obvious characteristic that sets birds apart from other modern vertebrates is the presence of feathers, which are modified scales. While vertebrates like bats fly without feathers, birds rely on feathers and wings, along with other modifications of body structure and physiology, for flight.

Detailed explanation-3: -Birds are warm-blooded vertebrates (vertebrates have backbones) and are the only animals with feathers.

Detailed explanation-4: -Birds are a group of warm-blooded vertebrates constituting the class Aves (/ˈeɪviːz/), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.