Form a Hypothesis: A scientist uses radioactive nitrogen to label the nitrogenous bases of the DNA of a cell. Then the DNA is allowed to replicate, and the new strands take up non-radioactive bases. Do one, both, or neither of the daughter cells have radioactive DNA? Explain.

The new strands took only non-radioactive bases during their replication. This implies that the radioactive bases did not get incorporated in the new strands. Also, according to semi-conservative mode of replication, one parental and one newly synthesized strand goes to the daughter cells. Since it is a hypothetical situation according to which parental strand has radioactive labeling, the radioactive strand will pass on to both the daughter cells.