Which of the following statements about extinctions is true?

Question

Quizplus · Accepted Answer

Option A is incorrect as it defines background extinction rate as that which occurs during a mass extinction, which is not true. The background extinction rate refers to the normal rate of extinction of species due to natural selection.
Option B is partially correct, but exaggerates the current extinction rates. While extinction rates are elevated due to human activities, they are not comparable to the extinction rates of the five mass extinctions.
Option C is correct. It is estimated that over 99% of all species that have ever existed on Earth are now extinct.
Thus, options B and C are correct and the answer is E.

Which of the Following Statements About Extinctions Is True