There are also snakes that give live birth.
Leaving your eggs lying about is risky.
However, the second statement about Australia, South America and Antarctica was separate and distinct from anything having to do with sharks.
Your response to that suggested that you thought it to be a long swim from Australia (with its marsupials) to anywhere else (with marsupials).
I didn't respond to anything about marsupials except how the marsupials would compete with sharks and run them into the sea. I think you just responded to the wrong posts. :-)
Some sharks.
There are also snakes that give live birth..
Some snakes.