Question

what happens to the dna double helix before dna replication can begin?
○ a. it ejects sugar molecules.
○ b. it condenses into chromosomes.
○ c. it shortens.
○ d. it unwinds between the base pairs.

Explanation:

Before DNA replication, the DNA double helix must unwind between the base pairs. This is done by helicase enzymes. Sugar molecules are part of the DNA structure and not ejected. Condensing into chromosomes occurs later in cell division (not directly before replication). Shortening is not a relevant step before replication.

Answer:

d. It unwinds between the base pairs.