Archeologists have found fossil remains of some of the first land animals in layer C. It has been suggested that C-14 be used to data the fossils. Some archeologists have objected and suggested that it would be best to use U-238 or Pb-206 to date the rock layer instead. Why would they make such a suggestion ? A) Rocks do not contain any elemental carbon for radiometric dating purposes .
B) Carbon-14 is only found in living things; it can only be used to date remains .
C) C-14 has a very short half-life, 5700 years, and based on geologic history , layer may be several million years old .
D) C-14 has such a long half -, 570000 million years, it would be more appropriate to use a radioactive element with a shorter half- life.