Complex sentence: Daru Island is one of the few of the Torres Strait Islands that do not belong to Australia, but to Papua New Guinea, and it is the most highly populated of all Torres Strait Islands, although scarcely any original Torres Strait Islanders live on the island.
Split into simpler sentences: Daru Island is one of the few Torres Strait Islands that do not belong to Australia, but to Papua New Guinea. It is also the most highly populated of the Torres Strait Islands, although scarcely any original Torres Strait Islanders live on the island.