Which of the following is not a result of hydrogen bonds?

a. two hydrogen atoms join together to form a molecule of hydrogen gas.

b. an enzyme has a unique shape that allows it to bond only with specific molecules.

c. two strands of dna are linked together taking a shape similar to a ladder.

d. some hair is straight, some wavy, and some very curly.

Answer is A. Two hydrogen atoms join together to form a molecule of hydrogen gas.

Explanation:

The electromagnetic attraction existing between hydrogen and other  electronegative atom, such as nitrogen or oxygen, is known as hydrogen bond. It can also be explained as the electromagnetic attraction occurring when hydrogen binds to a higher or larger atom such as nitrogen.

Note that , the bond existing between two hydrogen atoms resulting in the formation of a molecule of hydrogen gas is covalent bond. Covalent bond can simply be explained as the sharing of electrons.