And so what that means is there will be an enantomer that will exist with respect to this carbon. And this is the Nantomer shown here. So the D glycoaldehyde simply means that it's one of the Nantomers. And the L simply means it's the other type of anantomer. And we'll see exactly what the DNL represent in just a moment. So, once again, the simplest sugars are a monosaccharides and we call them carbohydrates because the empirical formula tells us they consist of carbon as well as water molecules.