One Important Reason We Do not Know Much About the Geologic

One important reason we do not know much about the geologic history of the Precambrian is that ______.

A) we have not yet been able to establish the half- lives for radioactive elements that existed in the Precambrian
B) rocks did not exist during much of that time
C) there are very few fossils preserved in Precambrian rocks
D) the climate was so harsh that erosion removed most of the rocks that formed during the Precambrian
E) radioactivity was not measurable during the Precambrian