Final answer:
The mineral required for the proper function of the thyroid gland is iodine, crucial for the synthesis of thyroid hormones T3 and T4, whose deficiency can cause thyroid dysfunctions.
Step-by-step explanation:
The iodine found in various foods and iodized salt is necessary for the proper function of the thyroid gland. Iodine is integral to the synthesis of thyroid hormones thyroxine (T4) and triiodothyronine (T3), which are critical for numerous physiological functions such as cellular oxidation, growth, reproduction, and activities of the central and autonomic nervous systems. The deficiency in iodine can lead to disorders like hypothyroidism, hyperthyroidism, and the enlargement of the thyroid gland, known as goiter.
Regarding the options provided, the correct answer is iodine, which is essential for the formation of T3 and T4 hormones in the thyroid gland. Without adequate iodine, the thyroid cannot produce these hormones effectively, leading to a range of health issues.