Which of the following is true regarding extinction?
a. Extinction that occurs in a relatively short period of time is referred to as background extinction.
b. Single events or several causes working together to produce extinction in a short period is referred to as mass extinction.
c. If the rate of speciation in a clade is equal to or less than the rate of extinction, the clade will survive.
d. The rate of extinction is steady from clade to clade as are the number of species contained within a clade.

Respuesta :

I would say that B) single events or several causes working together to produce extinction in a short period is referred to as mass extinction, but I am not 100% sure. 

I think it would be D. because in our text book it says and i quote

"The rate of speciation and extinction varies from clade to clade. Some clades contain many species that have survived for long periods of time. Other clades have only a few species, which soon become extinct."