单项选择题
In the following sentence, from which following aspects does the sentence extend the definition?
“An endangered species is a species (a population) of animals, plants or other organisms that is in danger of becoming extinct. This could happen because there are few of that animal left, its predators have grown in number, or the climate that it lives in is changing, or the places it lives in have been destroyed.”
A.Nationality.
B.History.
C.Features.
D.Working principles.