Antarctica has no counties.
No, Antarctica is a continent governed by the Antarctic Treaty.
Antarctica
The largest "county" in Antarctica is Alexander Island, which is an ice-covered landmass located near the western coast of the continent. However, it's important to note that Antarctica is not divided into traditional counties like in other regions, as it is governed by the Antarctic Treaty System.
I don't know about Australia, but Antarctica cannot participate because it has no real residents. The only people that live there are only living there temporarily and only to do scientific research. To participate in the olympics, a county must have some permanent residents to participate in all the events.
There are no countries in Antarctica.
Only one: Antarctica.
Antarctica is the only continent that the Antarctic Circle passes through.
Australia and Antarctica
There are no countries on the Antarctic continent, so there are no county definitions either.
That would be Antarctica.
Antarctica, I assume.
There are no settlements in Antarctica, only research stations.