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
Citroën Type B2 place between 28 October 1924 and 20 June 1925, and was the subject of much talk at the 19th Paris Motor Show in October 1924. In 1924 Poland bought 135 complete chassis of the B2 with Kégresse track (known as Citroën-Kegresse B2 10CV). Some were converted to all-terrain lorries while 90 were converted to Samochód pancerny wz. 28 armoured cars. Citroën Type B2 The Citroën B2 is the second model produced by Citroën. It is therefore the second European car to have been constructed according to modern mass production technologies. It was produced at André Citroën's factory in central Paris