F. A co-enzyme is basically an organic substance of low molecular weight that is not protein and that can unite with a given protein, apoenzyme, to form an active enzyme complex. Vitamin A Retinol, preformed Vitamin A is found only in animals. It is a fat soluble aliphatic alcohol usually found in fish liver oil. It is readily destroyed upon exposure to heat, light, or air. This vitamin has a direct role in vision and is a component of a pigment present in the retina of the eye.
Retinol is an antioxidant.
Beta-Carotene, provitamin A, is found in both plant and animals. It has potent antioxidant activity of its own. Recent studies have shown that Beta Carotene is extremely effective in protecting body cells from free radical damage, and it also bolsters the immune system. This is also a fat soluble vitamin. Vitamin A is an antioxidant which helps protect the cells against cancer.