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Scientists believe that _______ of species that once existed on Earth are now extinct.

A. about three-quarters
B. nearly half
C. about 40%
D. over 99 percent

User Ericfossas
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2 Answers

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Scientists believe that over 99% of species that once existed on Earth are now extinct.

D. over 99 percent
User UsefulBee
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The correct answer is D. Over 99 percent

Step-by-step explanation:

Life on Earth has existed for 4.28 billion ago and during this time billions of species have emerged including bacterias, fungi, plants, animals, etc. However, due to evolution, changes in the environment and massive extinction events most species that lived in other geological periods have completely disappeared or extinct. Indeed it is estimated by biologists and scientists that over 99% of the species that ever existed on Earth do not live today or are extinct this has been proposed based on the millions of fossils discovered that suggest multiple species that cannot be found nowadays and evidence that shows many more species are extinct and there is no or little evidence about them. Therefore over 99 percent of species that once existed on Earth are now extinct.

User Emandt
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