Prior to the 19th century, most scholars thought that the world was less than 10,000 years old. Based on geological and radiometric evidence, however, scientists now believe the age of Planet Earth is closer to:
a) 20,000 years old.
b) 100,000 years old.
c) one million years old.
d) 40 million years old.
e) four billion years old.
Ans: e) four billion years old.
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