<P> Mercer Quality of Living Survey ranks Sydney tenth in the world in terms of quality of living, making it one of the most livable cities . It is classified as an Alpha+ World City by GaWC . Melbourne also ranked highly in the world's most liveable city list, and is a leading financial centre in the Asia - Pacific region . </P> <P> Papua New Guinea is rich in natural resources, which account for two thirds of their export earnings . Though PNG is filled with resources, the lack of country's development led foreign countries to take over few sites and continued foreign demand for PNG's resources and as a result, the United States constructed an oil company and began to export in 2004 and this was the largest project in PNG's history . Papua New Guinea is classified as a developing economy by the International Monetary Fund . Strong growth in Papua New Guinea's mining and resource sector led to the country becoming the sixth fastest - growing economy in the world in 2011 . </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 . There are two major political groups that usually form government, federally and in the states: the Australian Labor Party and the Coalition which is a formal grouping of the Liberal Party and its minor partner, the National Party . Within Australian political culture, the Coalition is considered centre - right and the Labor Party is considered centre - left . </P> <P> Papua New Guinea is a Commonwealth realm . As such, Queen Elizabeth II is its sovereign and head of state . The constitutional convention, which prepared the draft constitution, and Australia, the outgoing metropolitan power, had thought that Papua New Guinea would not remain a monarchy . The founders, however, considered that imperial honours had a cachet . The monarch is represented by the Governor - General of Papua New Guinea, currently Bob Dadae . Papua New Guinea (and the Solomon Islands) are unusual among Commonwealth realms in that governors - general are elected by the legislature, rather than chosen by the executive branch . </P>

Why is australia considered to be a continent and not an island