Final answer:
Sweet potatoes are a good source of beta-carotene among the foods listed. Beta-carotene, precursor to vitamin A, is mostly found in orange and dark green vegetables and some fruits, not typically in grains or red cabbage, corn, and beets.
Step-by-step explanation:
Foods rich in beta-carotene include many fruits and vegetables with a deep orange color or, in some cases, dark green leafy vegetables. Among the options provided, sweet potatoes are a notable source of beta-carotene. This substance is not typically found in high amounts in red cabbage, corn, beets, or whole grains. It's important for students to understand that beta-carotene is a precursor to vitamin A, which is essential for healthy vision, immune function, and skin health.
To ensure a diet rich in beta-carotene, individuals should consume a variety of different vegetables each day, especially those that are dark green and orange, such as spinach, broccoli, and carrots, in addition to fruits like mango, papaya, and apricots. While whole grains are part of a balanced diet, they are not typically high in beta-carotene. Instead, they provide carbohydrates and fiber which are also important to health.