Why is the hypothalamus called the “master gland”?

The hypothalamus is called a master control center because it releases hormones that regulate the pituitary gland, which in turn influences other endocrine glands. Choice A is the best match: its stimulating hormones lead other glands to produce hormones. Calcium regulation is mainly associated with the parathyroid glands, and simply being in the brain does not make a gland a “master gland.”

AI-written and checked against the verified answer.