Which vitamin is primarily associated with eyesight in dim light and skin structure?

• A. Vitamin B2
• B. Vitamin A
• C. Vitamin C
• D. Vitamin D

Answer: (B)

The main idea tested is how vitamin A supports both vision in dim light and the health of skin. In the eye, vitamin A is converted into retinal, which combines with opsin to form rhodopsin, the light-sensitive pigment in rod cells. When light exposure occurs, rhodopsin breaks down and triggers a signal to the brain; regenerating rhodopsin requires vitamin A, so a deficiency impairs low-light vision, causing night blindness. For the skin, vitamin A helps maintain healthy epithelial tissues by regulating cell growth and differentiation, supporting the integrity of the skin and mucous membranes. Other vitamins don’t play this specific dual role as directly, so vitamin A best fits both functions.