Question

this diagram shows the beginning of the process of replication. which statement best describes how the strands were separated?
○ covalent bonds were broken by an enzyme to separate the nitrogen bases.
○ hydrogen bonds were broken by an enzyme to separate the nitrogen bases.
○ covalent bonds were broken by an enzyme to separate the sugar and phosphate groups.
○ hydrogen bonds were broken by an enzyme to separate the sugar and phosphate groups.

Explanation:

In DNA replication, the two strands of the DNA double helix are separated. The nitrogenous bases (A - T, C - G) are held together by hydrogen bonds. Enzymes (like helicase) break these hydrogen bonds to separate the strands. Covalent bonds (such as phosphodiester bonds between sugar - phosphate groups) are not broken in the initial strand separation step of replication.

Answer:

Hydrogen bonds were broken by an enzyme to separate the nitrogen bases.