Australia is the largest country by area in Oceania and the world’s sixth-largest country. Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. is a federal parliamentary constitutional monarchy, comprising six states and ten territories. Australia’s population of nearly 26 million is highly urbanized and heavily concentrated on the eastern seaboard.
Australia’s isolation from other continents explains much of the singularity of its plant and animal life. Its unique flora and fauna include hundreds of kinds of eucalyptus trees and the only egg-laying mammals on Earth, the platypus and echidna. Australia had moved to higher latitudes so that the alpine uplands that followed the deformation were covered by the nucleus of a continental ice sheet. Only the highest peaks stood prominently above the surface of the ice in the form of nunataks, and the little sediment available was carried off the continent in ice streams.