So we have the alpha and the beta animal. The alpha animal means that the hydroxyl group on the first carbon points in the opposite direction with respect to this group here, which is shown here, while the beta anamar, these two groups, point in the same exact direction. Now, inside our body, about two thirds exist in this beta form, one third exists in this alpha form. And a very, very small amount, less than 1%, actually exists in this deglucose open chain form. Now, as I mentioned, just a moment ago, we have the fissure projections that are basically used to describe the stereo chemistry, the arrangement and the three dimensional position of atoms for the open chain forms. On the other hand, we have the Holworth projections, which are used to describe the stereo chemistry of the cyclic sugars.