Meselson and Stahl carried out an investigation on DNA in bacteria. First, they cultured the bacteria in a medium containing only heavy nitrogen, $^{15}\text{N}$, until every bacterial DNA molecule had heavy nitrogen only. The bacteria were then transferred out of the heavy-nitrogen medium and grown in a medium containing only light nitrogen, $^{14}\text{N}$. Samples of bacteria were taken from each of the next three generations and the DNA was examined. Hybrid DNA has both heavy and light nitrogen. Which row indicates the correct DNA for the first and third generations?
- Afirst generation: all hybrid; third generation: half hybrid, half light
- Bfirst generation: all hybrid; third generation: one quarter hybrid, three quarters light
- Cfirst generation: half hybrid, half heavy; third generation: half hybrid, one quarter heavy, one quarter light
- Dfirst generation: half hybrid, half light; third generation: one quarter hybrid, three quarters light