A biologist used the radioisotope tritium (3H) to label thymine and the radioisotope carbon-14 (14C) to label uracil. She then incubated a growing bacterial culture with both labeled bases. After five hours of incubation, the biologist extracted polynucleotides from the cells and separated them into three groups, each containing a range of different polynucleotide lengths. The first group contained the shortest polynucleotides. The second group contained polynucleotides of midrange length, and the third group contained the longest polynucleotides. Then she determined the percentage of each radiolabel in each fraction. Her data are summarized in the table above. Which statement represents a reasonable hypothesis that could explain these results?Uptake of 3H label resulted from DNA replication, and uptake of 14C label resulted from transcription.