Question

hydrogen bonding is necessary for bonding carbon to oxygen. forming double - stranded dna molecules. decreasing the boiling point of liquids such as water. causing van der waals interactions.

Explanation:

Hydrogen - bonding holds the two strands of DNA together through complementary base - pairing. Carbon - oxygen bonding is covalent. Hydrogen bonding increases water's boiling point, not decreases it. Van der Waals interactions are different from hydrogen bonding.

Answer:

B. forming double - stranded DNA molecules