Sagot :
The two complementary strands of DNA are held together by Hydrogen bonding.
DNA strand and its complementary strand are held together by hydrogen bonds. A "G" (guanine) base on one strand will always be bonded to a "C" (cytosine) on the opposite strand by 3 hydrogen bonds. An "A" (adenine) base on one strand will always be bonded to a "T" (thymine) on the opposite strand by 2 hydrogen bonds.