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
Answer:C
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