In the Hershey-Chase experiment, what was this single difference?
a) Growing of the cells in the presence of different isotopes of nitrogen: first 15N and later 14N.
b) Labeling bacterial DNA or labeling bacterial proteins.
c) Growing of the cells in the presence of different isotopes of nitrogen: first 14N and later 15N.
d) Labeling viral DNA or labeling viral proteins.
