The gland that links the nervous system and the endocrine system, controls many of the pituitary gland functions, and regulates the body's water levels is the hypothalamus.
The correct answer is the hypothalamus. The hypothalamus is a small region of the brain that plays a crucial role in connecting the nervous system and the endocrine system. It controls many of the functions of the pituitary gland, which is often referred to as the "master gland" because it controls the secretion of hormones from other endocrine glands. Additionally, the hypothalamus helps regulate the body's water levels by producing the hormone vasopressin, also known as antidiuretic hormone (ADH), which acts on the kidneys to control water reabsorption. It is important to note that while the other options listed (thyroid, pancreas, and ovaries) are all important glands involved in hormone regulation, they do not have the specific role of linking the nervous and endocrine systems or controlling water levels in the same way as the hypothalamus.
