You decide to repeat the meselson-stahl experiment, except this time you plan to grow the e. coli cells on light 14n medium for many generations and then transfer them to heavy 15n medium and allow them to grow. if the semiconservative model of dna replication is correct, what is the expected distribution of dna in the density gradient after one round of replication

During crossing-over, a. genetic material is exchanged between nonsister chromatids, resulting in new combinations of alleles. b. nonsister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. c. one homologous chromosome of a tetrad is exchanged with another tetrad, resulting in new combinations of alleles. d. sister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. e. genetic material is exchanged between sister chromatids, resulting in new combinations of alleles.