Australia is a country in Oceania bordering the Indian Ocean and the Southern Pacific Ocean. Australia is comprised of mainland Australia, the island of Tasmania, and several small islands in the Indian and Pacific Oceans. The terrain is mostly low plateau with deserts. The government system is a federal parliamentary democracy and a commonwealth realm. The chief of state is the queen and the head of government is the prime minister. Australia has a mixed economic system in which the economy includes a variety of private freedom, combined with centralized economic planning and government regulation. Australia is a member of Asian Pacific Economic Cooperation (APEC) and the Trans-Pacific Partnership (TPP).