What are endemic species?

Endemic species are species that are native to a particular region or geographic area, and are found nowhere else in the world.
Alien (exotic) species are the species that have been intentionally or unintentionally brought into a new ecosystem by human activities. 
Cosmopolitan species are the species that have a wide geographic range and are found in multiple regions around the world. 
Critically endangered species, endangered species and vulnerable species are threatened with extinction due to habitat loss and other human activities.