A species whose populations has become so small that it may become extinct if not protected is a/an
Answer Details
An endangered species is a species whose populations have become so small that they may become extinct if not protected. This can be caused by a variety of factors, including habitat destruction, overhunting, and pollution. Endangered species are considered to be important to conserve because they contribute to biodiversity and the overall health of ecosystems. Therefore, the correct option is "endangered species".