And when we replicate DNA molecules, those two strands essentially separate. And when they separate, we can use DNA polymerase can use those templates to synthesize those new replicated polynucleotide chains. So the DNA polymerase can only add new nucleotides onto that growing polypeptide chain as long as the new nucleotides are complementary to the basis down on that template DNA molecule. Now let's move on to C. Another thing that DNA polymerase actually needs is a primer. So with the primer, we can initiate that DNA replication process. Now, what exactly is a primer?