"Extinct" refers to a species that no longer exists anywhere on Earth. This can happen due to various reasons, including habitat loss, climate change, overhunting, or the introduction of invasive species. When a species is declared extinct, it means that there are no living individuals left, and it cannot reproduce or recover. Famous examples of extinct species include the dodo, a flightless bird that lived on the island of Mauritius, and the woolly mammoth, a large prehistoric elephant. Conservation efforts aim to prevent extinction by protecting endangered species and their habitats, ensuring biodiversity for future generations.