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
LTA-B2 LTA-B2 LTA-B2 is an adaptive rowing classification. The classifications were developed and current as of March 2011. Rowing Australia defines this classification as "athletes with a visual impairment (LTA-B1, LTA-B2 and LTA-B3)" Rowers in this classification compete in single and sculls for club, state, and national competitions. In international competitions, they compete in mixed cox fours sculls, with a maximum of two visually impaired rowers in the boat. For the 2016 Summer Paralympics in Rio, the International Paralympic Committee had a zero classification at the Games policy. This policy was put into place in 2014, with the goal of avoiding