Answer:
tonga
Explanation:
Everybody knows what an island is, a piece of land entirely surrounded by water, it should be smaller than a continent, otherwise it would be a continent. With Australia one is not so sure, but the fact that Australia has its own tectonic plate justifies it as a continent.
Geology of Islands.
Some islands sit atop ancient submerged volcanoes rising from the ocean floor. Some low-lying tropical islands were formed from organic material of stony corals and other organic debris. Other islands are unsubmerged parts of the continental shelf, the shallow edge of a
