How Many Species Normally Go Extinct Each Year, as Estimated

Question

How many species normally go extinct each year, as estimated by scientists?
A) 1 species per thousand per year
B) 1 species per million per year
C) 1 species per billion per year
D) 1 species per year

Accepted Answer

Scientists estimate that the natural background rate of extinction is about 1 species per million species per year.