The evidence that scientists currently have suggests that life on earth __________.
a. began in the water
b. first evolved around 3,500 million years ago
c. began as single-celled organisms
d. a and b
e. all of the above
They think that life between in the water about 3,500 million years ago. They also believe that the first life form was a single cell organism. They can use radiometric dating in order to calculate time based on radioactive decay in rocks.
