And based on this, we can basically determine if the semiconservative process actually works. So this experiment has three important points. Number one is the original parental strands contain the N 15 isotopes and that's because they were initially grown in the N 15 rich medium b is or .2 is replicated daughter strands because now the medium is changed to the N 14. The replicated daughter strands will contain N 14 isotopes because as these daughter cells are synthesized we're going to take the nitrogen to synthesize the nitrogenous bases and sugars and so forth from this median that contains the M 14. So the newly synthesized strands will contain the regular N 14 isotope. But the other ones, the original will contain that labeled N 15 isotope.