The correct answer is the endocrine system.
The endocrine system is made up of different glands that send hormones out to the target cell; these hormones are chemical body messengers. The endocrine glands release hormones into the bloodstream. The endocrine system includes the pituitary gland, pineal, thyroid, parathyroid, and adrenal. Each of these glands become different functions which include:
The pituitary gland secretes different hormones, which are growth, prolactin, thyrotropin, antidiuretic, and oxytocin.
The thyroid gland secretes thyroid hormone, which includes the thyroxine and triiodothyronine. The parathyroid secrete parathyroid hormone.
The adrenal glands are divided into the adrenal cortex and medulla. The adrenal cortex secretes corticosteroids and adrenal medulla. It makes catecholamines. The pineal gland secretes melatonin.
These hormones aid function in the body like reproductive function, regulate water balance and ions and also control homeostasis.