What is the single unique characteristic that distinguishes extant birds from other extant vertebrates?
A)a hinged jaw
B)feathers
C)an amniotic egg
D)flight
E)a four-chambered heart

Question

Quizplus · Accepted Answer

Feathers are the single unique characteristic that distinguishes extant birds from other extant vertebrates. While other characteristics listed here are also important in distinguishing birds from other animals, feathers are only present in birds and are key features for their adaptation to flight, thermoregulation, and communication.

What Is the Single Unique Characteristic That Distinguishes Extant Birds