semi conservative model that’s on the back of our rg: P generation, N15, the DNA is in the ______ of the test tube. then, as it replicates the __ generation is half ___ and half ___. it’s in the ______ of the test tube. then, in the F2 generation, 2 strands are in the ___ of the test tube and two are in the ______ still. the graph shows us that it will be mainly ___, but never entirely because the ___ from the parent generation will still be there.