Question

The mammals with characters of both reptiles and mammals are
A. Marsupials
B. Monotremes
C. Cetacean
D. Rodents

Answer 1

Hint: Mammals- The most unique feature of this class named Mammalia is these posses milk-producing glands called mammary glands to nourish their news ones. They give birth to young ones. Reptiles are the members of class Reptilia have a creeping or crawling mode of locomotion. Their body is covered by dry and cornified skin which are epidermal scales. They are oviparous. The members cast their scales.

Step by step answer:Option -A- Marsupials
These come under the class Mammalia. The most unique feature of members of these marsupials is
they have an abdominal pouch. They carry their young ones in their abdominal pouch. They closely
resemble mammals i.e. they have mammary glands, ear bones, and true hair. A most common
example being kangaroo and koalas.
Option -B- Monotremes
They are the most primitive class of mammals. They possess both the characters of reptiles and
mammals. Like mammals they have hairs and their mothers milk their young ones i.e. they have
mammary glands to nourish their young ones. Unlike mammals, they don’t give birth to young ones.
They have reptile-like features i.e. lay eggs having very leathery shells and large yolks in their eggs.
Example duck-billed platypus and two spiny anteaters.
Option -C- Cetacean
These come under mammals these are aquatic mammals having the unique feature of the fat layer
or called blubber which is a protective layer to maintain the body heat in cold water. Examples
including dolphins, the beluga whale.
Option -D- Rodents
These are the members of the order Rodentia of family Mammalia. A most important feature of
them is having continuously growing a pair of incisors in each of the upper and lower jaws. They are
the most diversified mammals. Examples are rats, squirrels, guinea pigs, etc.
So, the correct answer to this question is the option” B” Monotremes.


Note: Mammals are the most advanced animals of the evolution. They have very distinct
morphological features that they have developed during evolution to survive the harshest conditions
whereas reptiles are crawling species that don’t have any most of the developed body features.