Final answer:
Vitamin A is essential to sight and is involved in the production of rhodopsin in the retina, crucial for low-light vision. Beta-carotene acts as a provitamin, converted into vitamin A in the liver. Deficiency in vitamin A can cause night blindness and even total blindness. The correct option is d.
Step-by-step explanation:
Vitamin A is essential to sight. This vitamin functions in the human body in four different forms, with Retinal being directly involved in the vision process. Your body can create vitamin A from a pigment found in certain plants known as carotene, which is essential for normal vision.
Vitamin A plays a crucial role in the production of rhodopsin, a pigment in the rod cells of the retina that is necessary for low-light vision.
Beta-carotene is a provitamin because it can be converted into vitamin A in the body. This conversion takes place mainly in the liver, with the aid of enzymes like β-carotene 15, 15'-oxygenase and the presence of a-tocopherol (vitamin E), which also acts as an antioxidant preventing the oxidative degradation that can be caused by free radicals.
A deficiency in vitamin A can lead to visual impairments, ranging from night blindness (inability to see well at low light levels) to total blindness. It's also important for healthy skin, bones, and teeth, as well as immune system development in young children. Option d. is the correct one.