What is the main characteristic feature of Aves?

Step-by-step solution

The main characteristic feature of Aves (birds) is the presence of feathers. Aves are warm-blooded animals, also known as homoiothermous, which means they are able to maintain a constant body temperature Mammals have two pairs of limbs, adapted for walking, running,climbing, burrowing, swimming or flyingThe most unique mammalian characteristic is the presence of milk producing glands (mammary glands) by which the young ones are nourished.Mammals have two pairs of limbs, adapted for walking, running,climbing, burrow