What is the primary function of the thyroid gland?

The thyroid gland plays a crucial role in regulating the body’s metabolism and maintaining overall energy levels. It achieves this by secreting hormones such as thyroxine (T4) and triiodothyronine (T3), which influence how the body uses energy.

Additionally, the thyroid is involved in the regulation of blood calcium levels through the production of calcitonin, a hormone that helps lower blood calcium levels. Given this dual responsibility of managing metabolism and calcium regulation, the primary functions of the thyroid gland are accurately represented in the chosen answer. This highlights the gland's critical role in ensuring metabolic processes run efficiently and that calcium levels remain stable in the bloodstream, both of which are essential for overall health.