And water is a polar molecule. So what that means is these bases which are predominantly non polar, will not once interact with that polar water solvent. And what this double helix structure ensures is that all these non polar bases are found inside the structure of the double helix and away from the polar water molecules. And so that is known as the hydrophobic effect. And these base cells will interact via the hydrophobic interactions and that will be a stabilizing effect. So we see that we have hydrogen bonds, we have London dispersion forces and we have the hydrophobic effect.