Final answer:
Vitamin E, found in vegetable oil, scavenges free radicals and serves as a potent antioxidant, safeguarding cellular components and other vitamins from oxidative damage.
Step-by-step explanation:
The substance found in vegetable oil which serves to scavenge free radicals and acts as an antioxidant is Vitamin E. Vitamin E, chemically known as alpha-tocopherol, is an oily substance that is heat stable and acts as a potent antioxidant. In the body, it helps protect cells by scavenging harmful by-products of metabolism such as free radicals, which are highly reactive due to their unpaired electrons. In addition to its presence in vegetable oils, Vitamin E also protects other vitamins like Vitamin A from oxidation and is a key antioxidant nutrient alongside vitamins A and C, beta-carotene, and selenium. The hydroxyl group on the aromatic ring of Vitamin E is responsible for donating a hydrogen atom to free radicals, stabilizing them and thus stopping the chain reaction of lipid oxidation in cell membranes.