a) Calcium: Important for bones and muscle function, but not directly involved in thyroid hormone production. b) Sodium: Maintains fluid balance and nerve function but is not essential for thyroid hormone synthesis. c) Bromine: Has no known essential role in human nutrition or thyroid function. d) Iodine: Iodine is a crucial component of thyroid hormones T3 (triiodothyronine) and T4 (thyroxine). Without iodine, the thyroid cannot synthesize these hormones. e) Potassium: Important in nerve impulse transmission and muscle contraction, not thyroid function.