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Author Question: What is the single unique characteristic that distinguishes extant birds from ot (Read 488 times)

federox

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on: Aug 8, 2013
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


theo

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Reply #1 on: Aug 10, 2013
E) a four-chambered heart
Answer has to be B, 100% :D


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