While exploring a coal mine, scientists found plant fossils in the ceiling of the mine which had been preserved by an earthquake. samples taken from one of the fossils have carbon-14 activities of 40.0 counts/min. a reference sample of the same size, from a plant alive today, has a carbon-14 activity of 160.0 counts/min. if carbon-14 has a half-life of 5730 years, what is the age of the plant fossil in years?

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.