So the thing that holds our two strands of DNA together to form our double helix are hydrogen bondings or hydrogen bonds between adjacent or opposite nucleotide, specifically our nitrogenous basis. So we have this nucleotide, which is right next to this nucleotide, and the bonding takes place between our adjacent or complementary nitrogenous bases. So guanine always forms hydrogen bonds with cytosine, while our Adamine always forms hydrogen bonds with arithymine. And notice in the case of guanine and cytosine, we have three hydrogen bonds. And in the case of adenine and thymine, we only have two of these hydrogen bonds. So that means the guanine cytosine pair forms a more stable attraction than our adenine, thymine.