Final answer:
Selenium is the nutrient that serves as a cofactor in antioxidant enzyme systems, essential for the function of enzymes like glutathione peroxidase. Vitamin E, superoxide dismutase, and calcium serve other roles in the body's defense against oxidative damage. The option (A) is correct.
Step-by-step explanation:
The nutrient that is a cofactor in antioxidant enzyme systems is selenium. Selenium is vital for the proper function of enzymes like glutathione peroxidase, which protects the body from oxidative damage by reducing peroxide radicals. Other antioxidants such as Vitamin E, superoxide dismutase, and calcium perform different roles.
Vitamin E acts as a scavenger of harmful by-products of metabolism, known as free radicals, to prevent oxidative damage. Superoxide dismutase, on the other hand, involves metal ions like copper and zinc, not selenium, as essential components. Calcium is important for many bodily functions including nerve function and water balance but is not a cofactor of antioxidant enzyme systems. Therefore, option (A) is correct.
This question is not complete, Here I am attaching the complete question:
Which nutrient is a cofactor in antioxidant enzyme systems?
(A) Selenium
(B) Vitamin E
(C) Superoxide dismutase
(D) Calcium