Following the reptilian extinctions at the close of the Mesozoic,two groups of mammals,the marsupials and ________,evolved.
A)eukaryotes
B)cephalopods
C)trilobites
D)placentals
E)stromatolites

Question

Quizplus · Accepted Answer

The two groups of mammals that evolved after the reptilian extinctions at the close of the Mesozoic are marsupials and placentals. While marsupials give birth to relatively undeveloped young that complete their development outside of the womb, placental mammals have a placenta that delivers nutrients and oxygen to the developing fetus, allowing for more advanced development before birth.

Following the Reptilian Extinctions at the Close of the Mesozoic,two