This type of fossil forms from a mold. Small particles of mud, sand, and/or minerals becomes packed into the open space of the mold in the shape of a
turtle shell and hardens. The result is a fossil that has the same exact shape
as the original turtle shell.

The hershey and chase experiments involved the preparation of two different types of radioactively labeled phage. which of the following best explains why two preparations were required? a. the bacteriophage used in the experiments was a t2 phage. b. it was necessary that each of the two phage components, dna and protein, be identifiable upon recovery at the end of the experiment. c. each scientist had his own method for labeling phage, so each conducted the same experiment using a different isotope. d. establishing the identity of the genetic material required observation of two phage generations.