Vitamin amino acids. Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, vitamin E consists of four tocopherols and four tocotrienols. The thirteen vitamins required by human metabolism are: vitamin A (retinols and carotenoids), vitamin B (thiamine), vitamin B (riboflavin), vitamin B (niacin), vitamin B (pantothenic acid), vitamin B (pyridoxine), vitamin B (biotin), vitamin B (folic acid or folate), vitamin B (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (quinones). Vitamins have diverse biochemical functions. Some forms of vitamin A function as regulators of cell and tissue
B2 (classification) approach the wall. The swimmer has to bring their own tapper, but having a tapper is optional. In blind cricket, B2 batsmen have the option of having a runner. There are some rule differences for this class in competition that are sport specific and which differ from able bodied versions of the sport. In adaptive rowing's Coxed Four, LTA4+, the maximum number of vision impaired rowers in a boat is two. In blind cricket, three players in this class are required to be on the field at the same out of the eleven total players on the pitch. B2 batsmen