DNA replication in bacteria was studied. The bacteria were first cultured in a medium containing only heavy nitrogen, $^{15}\text{N}$, until every bacterial DNA molecule became heavy. The bacteria were then transferred from the heavy nitrogen medium and grown in a medium containing only light nitrogen, $^{14}\text{N}$. This produced the first generation. The bacteria went on to divide again, and a sample was taken from the second generation and the DNA examined. Hybrid DNA is made up of both heavy and light DNA. Which row shows the correct result for the second generation?
- Apercentage of heavy DNA strands: 25; percentage of hybrid DNA molecules: 25
- Bpercentage of heavy DNA strands: 25; percentage of hybrid DNA molecules: 50
- Cpercentage of heavy DNA strands: 50; percentage of hybrid DNA molecules: 25
- Dpercentage of heavy DNA strands: 50; percentage of hybrid DNA molecules: 50