Over the past 400 years, humans have documented the extinction of more than ________ species. This modern rate of species extinction is estimated to be ________ the normal extinction rate seen in the fossil record.
A) 100; about the same as
B) 400; about double
C) 1,000; over 100 times greater than
D) 10,000; at least 1 million times greater than

Question

Quizplus · Accepted Answer

Scientists estimate that over the past 400 years, humans have documented the extinction of more than 1,000 species. This modern rate of species extinction is estimated to be over 100 times greater than the normal extinction rate seen in the fossil record. Option A is incorrect because the number of documented extinctions is much higher than 100. Option B is incorrect because the modern rate of species extinction is estimated to be more than double the normal extinction rate seen in the fossil record. Option D is incorrect because the modern rate of species extinction is estimated to be at least 100 times greater than the normal extinction rate seen in the fossil record, not at least 1 million times greater.

Over the Past 400 Years, Humans Have Documented the Extinction