Question

Which of the following groups of animals bear a pouch outside the mother's body for carrying their young one?
A)Marsupials
B)Amniotes
C)Placentals
D)Monotremes
E)Prokaryotes

Answer 1

Mammals ('breast' from Latin mamma) are a category of vertebrate animals that make up the Mammalia class and are distinguished by the presence of mammary glands that provide milk for feeding (nursing) their young in females, a neocortex (a brain region), fur or hair, and three middle ear bones.

Complete answer:
Marsupial is a subclass of mammals distinguished by the appearance for some time after birth of an abdominal pouch to hold their underdeveloped youngsters. A main feature of amniotes is the presence of fluid-filled sacs (amnions) around the embryo during its development. Three types, including reptilia, aves and mammalia, include amniotes. The growth of a placenta to promote the sharing of materials between the mother and the foetus is characterized by placental mammals.

When embryonic development is complete and young people are born at a more advanced stage than marsupials, the placenta allows the young to stay within the mother's body. Monotremes are egg-laying mammals, and unicellular species lacking any established nucleus and membrane bound cell organelles are called prokaryotes.

Hence, the correct answer is option (A)

Note: Around 90 million years ago, Marsupial diverged from Eutherian mammals. In North America, Marsupials possibly developed, spread into South America and Asia's Pacific rim. In the late Cretaceous or early Tertiary period, marsupials started to migrate from North America to Australia and New Zealand.