What must occur before replication can begin?

The two DNA strands must separate

Explanation:

This separation is mediated by DNA helicases enzymes. Using ATP energy, they breakdown the hydrogen bonds between the two strands of the double helices giving access of DNA polymerase to single-stranded DNA required for replication. The DNA polymerase can only bind to single-stranded DNA.

answer; i believe its (ovulation);

evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.