Extinction
a. only happens above the species level
b. cannot happen to more than one species at a time
c. has happened to over 99% of species that ever lived on earth
d. happens when a species or population dies out

The correct answer should be C. has happened to over 99% of species that ever lived on earth. As a matter of fact, historically there have been over five billion species since they first started appearing millions of years ago, but 99% of them are now extinct, mostly due to things like the Great Extinction in the paleozoic era. Human caused extinction is nowhere near the numbers that the nature has reached.

Nine months old i think but i’m not that sure