Answer:
hypothalamus
Step-by-step explanation:
The hypothalamus refers to the brain part comprising a variety of small nuclei with varying functions. One of the hypothalamus ' most important functions is to connect the nerves via the pituitary gland into the endocrine system.
The hypothalamus is indeed a brain system consisting of different nuclei and less anatomically distinct regions. It's discovered across all nervous systems of the vertebrates. Thus, from the above we can conclude that the correct option is A .