It also actually needs magnesium ions because these magnesium ions essentially increase the efficiency of these DNA polymerase molecules. And we'll discuss that in much more detail when we'll discuss the DNA replication process. Now D, so D is more of a fact about DNA polymerase molecules. And what D tells us is DNA polymerase can actually correct its own mistakes. So if the DNA polymerase accidentally mismatches a base, it can actually go back, remove that base and put in the correct base that it basically mismatched. And what that means is the DNA polymerase rarely makes mistakes.