Tim is overweight. His physician has decided to test him to see if there is a problem with the regulation of his metabolism. Which endocrine gland will be the focus of diagnostic testing?

A) adrenal
B) thymus
C) thyroid
D) pancreas

The thyroid gland plays a key role in regulating metabolism, so if there is a problem with metabolism regulation, the thyroid gland would be the focus of diagnostic testing. The adrenal gland is responsible for producing hormones such as cortisol and adrenaline in response to stress, but would not necessarily be specifically tested in this scenario. The thymus gland is primarily involved in the development of the immune system and would not be relevant to metabolism regulation testing. The pancreas is responsible for producing insulin to regulate blood sugar levels and may be tested in cases of diabetes, but would not necessarily be the focus of testing for metabolism regulation.