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. And when it does make a mistake, it can basically fix that mistake on its own accord. In fact, for every 100 million nucleotides that the DNA polymerase lays down correctly, it only makes one mistake and that's a very, very high accuracy. So DNA polymerase has the ability to remove and replace nucleotides that have been incorrectly placed.