Questions: Which of the following BEST explains the role of DNA polymerase? To join the adjacent Okazaki fragments. To unwind the DNA double helix. To build the RNA primer. To assemble daughter nucleotides on the parent strand.

The answer is the fourth one: To assemble daughter nucleotides on the parent strand.

Explanation for each option:

1. To join the adjacent Okazaki fragments: This is incorrect. The enzyme responsible for joining Okazaki fragments is DNA ligase, not DNA polymerase.
2. To unwind the DNA double helix: This is incorrect. The enzyme responsible for unwinding the DNA double helix is helicase, not DNA polymerase.
3. To build the RNA primer: This is incorrect. The enzyme responsible for synthesizing the RNA primer is primase, not DNA polymerase.
4. To assemble daughter nucleotides on the parent strand: This is correct. DNA polymerase is the enzyme that adds nucleotides to the growing daughter strand during DNA replication, using the parent strand as a template.

Summary: DNA polymerase's primary role is to assemble daughter nucleotides on the parent strand during DNA replication.