A deficiency in which mineral leads to thyroid deficiency?

The correct answer is Iodine.

Iodine is a mineral that is essential for the production of thyroid hormones, which regulate metabolism, growth, and development. A deficiency in iodine can lead to thyroid deficiency, which can cause a range of symptoms including fatigue, weight gain, constipation, dry skin, and hair loss. In severe cases, iodine deficiency can lead to goiter, which is an enlargement of the thyroid gland.