Western Ghats have a large number of plants and animal species that are not found any where else. Which of the following terms is used to notify such species?

Endemic species are those that are native and restricted to a specific region or geographic area and are not found naturally anywhere else in the world. Western Ghats is known for its rich biodiversity and high
endemism. It harbors a significant number of plant and animal species that are unique and found nowhere else on the planet.
(1) Threatened species refer to plant or animal species that are at risk of becoming endangered or extinct.
They are categorised as vulnerable, endangered, or critically endangered based on their declining population and the threats they face.
(2) Keystone species are species that have a disproportionately large impact on their ecosystem relative to their abundance. They play a critical role in  maintaining the structure, diversity, and functioning of an ecosystem. The loss of a keystone species can have significant consequences for the entire ecosystem.
(4) Vulnerable species are those that are at a higher risk of becoming endangered in the near future.