The problem here is these strands actually consist of a single strand and in DNA molecules we have two different strands. So in RNA molecules because they exist predominantly as a single strand these complementary sequences here and here. So the blue and the red come from that same polynucleotide chain. But in DNA the complementary sequences in the double helix structure come from two opposite polynucleotide chains. So that's the difference between the double helix in DNA and the double helix in RNA molecules. So we have these complementary sections that interact to form hydrogen bonds and that's a stabilizing effect.