Final answer:
The only Australian state that is not part of the mainland is Tasmania. Tasmania is separated from the mainland by the Bass Strait and is known for its natural beauty. The majority of Australia's population is concentrated in urban areas along the coastline.
Step-by-step explanation:
The only Australian state that is not part of the mainland is Tasmania. Tasmania is an island state, located 240 kilometers to the south of the Australian continent, separated by the Bass Strait. The other states, namely New South Wales, Victoria, and Queensland, are all located on the mainland. Tasmania is known for its rugged wilderness and is part of Australia's federal division along with the other states and territories.
As for the distribution of Australia's population, it is heavily concentrated in the urban areas along the coastlines. About 90 percent of the population live in cities. Sydney is the largest city located in New South Wales, followed by other major cities like Melbourne, Brisbane, Perth, and Adelaide. The federal capital is Canberra, located within the Australian Capital Territory. Australia's interior is much less populated due to the vast deserts, such as the Gibson Desert, Great Victoria Desert, and Great Sandy Desert.
Australia itself is part of the wider region known as Australasia, which also includes the island of Papua New Guinea, as well as islands in the Pacific Ocean. The region of Oceania of which Australia is part includes thousands of islands in the Pacific Ocean and larger landmasses like New Zealand and Papua New Guinea.