What is the single unique characteristic that distinguishes extant birds from other extant vertebrates?
A) endothermy
B) feathers
C) an amniotic egg
D) flight
E) a four-chambered heart
Answer: B
What is the single unique characteristic that distinguishes extant birds from other extant vertebrates?
A) endothermy
B) feathers
C) an amniotic egg
D) flight
E) a four-chambered heart
Answer: B
If the answers is incorrect or not given, you can answer the above question in the comment box. If the answers is incorrect or not given, you can answer the above question in the comment box.