_____________ is the major precursor for vitamin A and is found in carrots and orange vegetables.

The major precursor for vitamin A that is found in carrots and other orange vegetables is beta carotene. It is a carotenoid, which gives these foods their characteristic color. In the body, beta carotene is converted into retinol, the active form of vitamin A, which is crucial for various physiological functions, including vision, immune function, and skin health.

Beta carotene is abundant in many colorful fruits and vegetables, particularly those that are orange or yellow, such as carrots, sweet potatoes, and pumpkin. The conversion process involves enzymatic reactions in the intestinal mucosa and liver, where beta carotene is cleaved to produce retinol. This connection highlights the importance of diet in maintaining adequate vitamin A levels and indicates why foods rich in beta carotene are often recommended for overall health.

The other compounds mentioned, including lycopene and alpha carotene, do not serve as the primary precursor for vitamin A like beta carotene does, and retinol itself is the end product of beta carotene metabolism rather than a precursor.