1. 0 que são vitaminas e por que são essenciais para - funcionamento do organismo humano? 2. Qualé a principal função da vitamina D no corpo humano e o que pode ocorrer em caso de sua deficiência? 3. Explique a importância da vitamina C no sistema imunológico e no processo de cicatrização de feridas.

1. Vitamins are organic compounds that are essential for the normal functioning of the human body. They are necessary for various metabolic processes and help to maintain overall health. Vitamins are classified into two main groups: fat-soluble vitamins (A, D, E, and K) and water-soluble vitamins (B-complex vitamins and vitamin C). Each vitamin has specific functions and is involved in different physiological processes.<br /><br />2. The main function of vitamin D in the human body is to help regulate the absorption of calcium and phosphorus from the digestive tract. It promotes the formation and maintenance of bones and teeth, and it is essential for the proper functioning of the immune system. In case of vitamin D deficiency, it can lead to a condition called rickets in children, characterized by softening and weakening of the bones. In adults, it can cause osteomalacia, which is the softening of the bones, and it may also increase the risk of certain diseases, such as cardiovascular disease and certain types of cancer.<br /><br />3. Vitamin C, also known as ascorbic acid, is an essential nutrient for the proper functioning of the immune system and for the process of wound healing. It is involved in various immune functions, such as the production of white blood cells and the activation of certain immune cells. Vitamin C also plays a role in the synthesis of collagen, a protein that is essential for the formation of new tissues and for the repair of damaged tissues. Therefore, it is important for the healing of wounds and for the maintenance of healthy skin. In addition, vitamin C acts as an antioxidant, protecting cells from damage caused by free radicals.