I would say that it is the bond called complementary hydrogen bonds
Explanation:
The nucleotides in a base pair are complementary which means their shape allows them to bond together with hydrogen bonds. The A-T pair forms two hydrogen bonds. The C-G pair forms three. The hydrogen bonding between complementary bases holds the two strands of DNA together.
Since the speed in which the gas molecules are faster as they are heated, they fly around in the container and logically, it is harder to insert a moving object into water than something more stationary or slower.
