Question

Egg-laying mammals are found
(a)India
(b)South Africa
(c)Africa
(d)Australia

Answer 1

Egg-laying mammals are found in a place which is the smallest continent and the sixth-largest country in the world. Pouched animals like kangaroo along with these mammals are also limited to just this continent.

Complete answer:
Egg-laying mammals belong to subclass Prototheria which is regarded to be the most primitive mammals. They are only restricted to Australia and its neighboring islands. This may have happened due to the continental drift that occurred a million years ago. This continental drift is hypothesized to be the reason behind the splitting of the Australian continent from the Gondwana supercontinent.

Additional Information:
Prototherians have some characteristics of reptiles also such as they have a cloaca. It is a common outlet of intestinal, urinary as well as genital tracts. Also, their egg contains ample amounts of yolk for the developing embryo. Platypus and Echidna are examples of egg-laying mammals.
Platypus or Ornithorhynchus lays eggs in the nest. Its beak is broad just as a duck, hence it is commonly called duck-billed platypus. Pinnae are absent. Mammary glands are present but with the absence of nipples or teats. It exhibits sexual dimorphism as a male can be distinguished from females due to the presence of a poisonous organ known as a spur on each of their hindlimbs. Platypus is considered as a connecting link between the reptiles and mammals.

Echidna or Tachyglossus (Spiny Anteater) is commonly found in Australia and Tanzania. The hair on their body is modified into pointed spines, hence, the name Spiny Anteater. Its characteristic feature is Gynaecomastia where male Echidna also has mammary glands to feed the young ones. They can roll their body into a ball to scare away their predators. Pinnae, as well as the tail, is absent.
So, the correct answer is ‘ Australia’.

Note: All mammals are hairy bodied, warm-blooded, and have mammary glands. Oil glands and sweat glands are also present. Each ear consists of three parts: external, middle, and internal ear. Pinnae is a part of the external ear which have not been found in prototherians. But they do have three ear ossicles namely incus, malleus, and stapes just like any other mammal.