Fossils in Precambrian rocks are rare, while there are many fossils in rocks from the Phanerozoic eon. What does this evidence suggest?
A. There was a major change in the diversity of life in the Phanerozoic eon, probably due to mass extinction.
B.There was no life in the Precambrian eon.
C.The rocks from the Phanerozoic eon are much harder than those from the Precambrian eon.
D.There was no change in the diversity of life in the Phanerozoic eon.

Question

Fossils in Precambrian rocks are rare, while there are many fossils in rocks from the Phanerozoic eon. What does this evidence suggest?
A. There was a major change in the diversity of life in the Phanerozoic eon, probably due to mass extinction.
       B.There was no life in the Precambrian eon.
       C.The rocks from the Phanerozoic eon are much harder than those from the Precambrian eon.
       D.There was no change in the diversity of life in the Phanerozoic eon.

anonymous · Answer

The first question has a bit of a problem. Rocks of the Precambrian are rare. Sedimentary rocks are easily metamorphosed and any fossils in them are destroyed. So, unchanged Precambrian sedimentary rocks are very rare. Also, the Precambrian life forms did not have hard parts like shells or teeth. Their soft bodies were not favored for fossilization. So you can see that there is more going on than just the fact that there was an apparent explosion of life forms at the end of the Precambrian (choice D). 

Your chances of becoming a fossil are enhanced if you are removed from predation by scavengers. This is done by rapid burial. In addition, as mentioned above, hard parts also favor potential fossilization. Fossil sponges are rare but "sea shell" fossils are very common... so that is choice "C".

anonymous · Answer

thanks, even though you copied that from a yahoo answer from 4 years ago :b

anonymous · Answer

Yes I do...hope it help :)