Question

explain, in terms of the theory of continental drift ,why marsupial and
egg- laying mammals are found in Australia and not in any other continent. support explanation with the theory of continental drift? i need short answer pleas
help me pleas

Answer 1

The egg laying mammals and australian marsupials were originated in australia which was intially part of main land but due to continental drift or due to formation of geographical barrier between australia and the other continents it got seperated to the mainland.... So the distribution of the marsupials and egg laying mammals became restricted to the australia only as these species could not move to the other continents....and remained discontinued... This was due to geographical barrier not due to natural and climatic barrier... For this question best answer should be restricted distribution but as that is not in option then more related answer would be discontinuos distribution...(as discontinuos distribution is actually the distribution of closely related species in different areas of geography ,which were originated in same area but got seperated due to the geographical seperation without leaving any members in the interveining zone...

OR

1. Australia separated from other continents before evolution of Eutherian mammals.
2. Stock of primitive mammals, that survived on the Southern continent after continental drift, later diverged and evolved in marsupials which are found nowhere in the world.
3. Few of the earliest type egg laying mammals have also survived in Australia.