Which of These Characteristics Added Most to Vertebrate Success in Relatively

Question

Which of these characteristics added most to vertebrate success in relatively dry environments?
A) the shelled, amniotic egg
B) the ability to maintain a constant body temperature
C) two pairs of appendages
D) bony scales
E) a four-chambered heart

Accepted Answer

The shelled, amniotic egg allows for reproduction on land, independent of aquatic environments. This adaptation provided a significant advantage to vertebrates by enabling them to spread and diversify in relatively dry environments. The other options may have contributed to vertebrate success in various ways, but the shelled, amniotic egg was the most crucial adaptation for living on land.