Question

The existence of marsupials in Australia and New Zealand prove:
A. Genetic drift
B. Geological period
C. Continental drift
D. Both B and C

Answer 1

Hint: Australia and New Zealand were geographically located on the same continent once upon a time. It means they were part of the same continental plate before the drift occurred. This could be the reason behind the existence of marsupials in Australia and New Zealand.

Complete answer: Marsupials belong to the Mammalian infraclass Marsupialia. These animals carry their young in a pouch called ‘marsupium’. These extant members are endemic species of Australia, America and also found in Oceania.

According to Charles Darwin, Marsupials were considered inferior to placental mammals. These animals lived where there was no competition. This indicates absence of natural selection. Marsupial existence in Australia and New Zealand (Oceania) gives us an idea about the primitive geological period. It is evident that the continents were joined initially.

The separation of an intact continent due to various natural forces and its division into two different continental plates is known as continental drift. According to the continental drift theory, millions of years ago, South America and Australia were joined. This joined continent was present in the Southern hemisphere.
The marsupials lived there and moved freely, they must have migrated between these islands. So, even after separation or division of the continental parts, the marsupials are found in these regions.
This proves both the continental drift theory right and indicates about the related geological period. But the geological period itself cannot be a reason for such an occurrence. Continental drift is a justified explanation for the statement mentioned in the question.

Hence, the correct option is C. Continental drift.

Note: New Zealand is physically or geographically situated in a separate island from Australia.
The pieces of the Earth’s crust are known as tectonic plates or continental plates. There are seven major plates, viz. Pacific plate, North American plate, Eurasian plate, African plate, Antarctic plate, Indo-Australian plate and South American plate.