On January 1, 1901 the Australian nation emerged as a federation. The Australian continent was colonized by the United Kingdom in 1788, who subsequently established six self-governing colonies there. In the 1890s the governments of these colonies all held referendums on becoming a unified, independent nation. When all the colonies voted in favour of federation, the Federation of Australia commenced, resulting in the establishment of the Commonwealth of Australia in 1901. Whilst the Federation of Australia emerged in 1901, the States of Australia remained colonies of Britain until 1986 when the UK and Australia passed the Australia Acts. The model of Australian federalism adheres closely to the original model of the United States of America, though through a Westminster system. Australia is a continent comprising mainland Australia, Tasmania, New Guinea, Timor, Seram, and neighbouring islands. The continent is sometimes known in technical contexts by the names Sahul, Australinea or Meganesia, to distinguish it from the Australian mainland. It is the smallest of the seven traditional continents in the English conception. New Zealand is not part of the continent of Australia, but of the separate, submerged continent of Zealandia. Zealandia and Australia are both part of the wider regions known as Australasia and Oceania. The continent of Australia lies o
a continental shelf overlain by shallow seas which divide it into several landmasses Ч the Arafura Sea and Torres Strait between mainland Australia and New Guinea, and Bass Strait between mainland Australia and Tasmania. When sea levels were lower during the Pleistocene ice age, including the last glacial maximum about 18,000 BC, they were connected by dry land. During the past ten thousand years, rising sea levels overflowed the lowlands and separated the continent into today's low-lying arid to semi-arid mainland and the two mountainous islands of New Guinea and Tasmania. Geologically, a continent extends to the edge of its continental shelf, so the now-separate islands are considered part of the continent. Due to the spread of animals, fungi and plants across the single Pleistocene landmass the separate lands have a related biota. A referendum (also known as a plebiscite or a vote on a ballot question) is a direct vote in which an entire electorate is asked to either accept or reject a particular proposal, usually a piece of legislation which has been passed into law by the local legislative body and was signed by the pertinent executive official(s). This may result in the adoption of a new constitution, a constitutional amendment, a law, the recall of an elected official or simply a specific government policy. It is a form of direct democracy.