(c) Human body cannot synthesize micronutrients and vitamins such as vitamin A, B1 (thiamine), B2 (riboflavin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), B12 (cobalamin), E and K. Although the human body can synthesise vitamin B3 (niacin), vitamin D.