Scientists have estimated the Earth to be approximately __________ years old.
A.
6.4 million
B.
4.6 million
C.
6.4 billion
D.
4.6 billion
1 answer
D. 4.6 billion
A.
6.4 million
B.
4.6 million
C.
6.4 billion
D.
4.6 billion
1 answer