Question

Which of the following is true regarding extinction?

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

Answer 1

The statement that is true here about extinction is

C. Single events or several causes working together to produce extinction in a short period is referred to as mass extinction.

An example of this would be when one important event such as a meteorite hitting Earth further influences our planet by destroying habitable environment, polluting water, etc.

All of this then causes a mass extinction because it's not habitable for multiple species anymore.