Question

‌ ‌Which of the following is not viviparous?
A. Mole
B. Platypus
C. Kangaroo
D. Shrew

Answer 1

‌ ‌Hint:‌ ‌‌ ‌Viviparous organisms are those that give birth to organisms rather than laying eggs. Some mammals also lay eggs like platypus and echidnas.

Step‌ ‌by‌ ‌step‌ ‌answer:‌
Viviparous organisms are those that give birth to live babies rather than laying eggs. The developing embryo of that organism is not enclosed by a calcareous shell. The viviparous organism tends to their young by feeding them breast milk. It is highly nutritious to the developing young. The platypus is a mammal that is endemic to the Australian landmass. They have large snouts with a duck-like beak to catch food. They also have a beaver-like tail to move/ swim in the water bodies. This organism is an oviparous animal that lays eggs.

Hence option B is correct.

Additional Information:
-Ovoviviparous organisms are those that lay eggs into a pouch present within and give birth to live babies. Examples of ovoviviparous organisms include several species of sharks. In the case of the great white shark, the mother lays hundreds of eggs but it gives birth to only one or two live babies. This is because the hatched baby shark in the pouch devours the other eggs and immature hatched sharks and develops fast. This ensures the survival of the fittest.
-Viviparous organisms are moles, kangaroos, and shrews. Shrews are the earliest of all the mammals to develop.
-Platypuses are mildly venomous. Their venom isn’t potent enough to kill humans even though they can kill smaller mammals like dogs, etc.
-Many birds, reptiles, amphibians, and some arthropods are oviparous. The eggs of amphibians are not covered by a calcareous shell. Rather they are covered by a mucous and gelatinous layer.

Note:‌ ‌‌ ‌Other oviparous animals include echidna, monotreme, prototheria, etc.
They incubate the eggs for a varied period of time.