<P> Australian forests are mostly made up of evergreen species, particularly eucalyptus trees in the less arid regions; wattles replace them as the dominant species in drier regions and deserts . Among well - known Australian animals are the monotremes (the platypus and echidna); a host of marsupials, including the kangaroo, koala, and wombat, and birds such as the emu and the kookaburra . Australia is home to many dangerous animals including some of the most venomous snakes in the world . The dingo was introduced by Austronesian people who traded with Indigenous Australians around 3000 BCE . Many animal and plant species became extinct soon after first human settlement, including the Australian megafauna; others have disappeared since European settlement, among them the thylacine . </P> <P> Many of Australia's ecoregions, and the species within those regions, are threatened by human activities and introduced animal, chromistan, fungal and plant species . All these factors have led to Australia's having the highest mammal extinction rate of any country in the world . The federal Environment Protection and Biodiversity Conservation Act 1999 is the legal framework for the protection of threatened species . Numerous protected areas have been created under the National Strategy for the Conservation of Australia's Biological Diversity to protect and preserve unique ecosystems; 65 wetlands are listed under the Ramsar Convention, and 16 natural World Heritage Sites have been established . Australia was ranked 3rd out of 178 countries in the world on the 2014 Environmental Performance Index . </P> <P> Australia is a federal parliamentary constitutional monarchy with Elizabeth II at its apex as the Queen of Australia, a role that is distinct from her position as monarch of the other Commonwealth realms . The Queen is represented in Australia by the Governor - General at the federal level and by the Governors at the state level, who by convention act on the advice of her ministers . Thus, in practice the Governor - General has no actual decision - making or de facto governmental role, and merely acts as a legal figurehead for the actions of the Prime Minister and the Federal Executive Council . The Governor - General does have extraordinary reserve powers which may be exercised outside the Prime Minister's request in rare and limited circumstances, the most notable exercise of which was the dismissal of the Whitlam Government in the constitutional crisis of 1975 . </P> <P> The federal government is separated into three branches: </P>

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