Final answer:
Oxytocin is the hormone that acts on the brain and benefits the body. It is produced by the hypothalamus and has various functions in the body.
Step-by-step explanation:
The hormone that acts on the brain and also benefits the body is called oxytocin. Oxytocin is synthesized by the hypothalamus in the brain and is released by the posterior pituitary gland. It has various functions, including stimulating uterine contractions during childbirth, facilitating milk letdown during lactation, and regulating body processes such as water reabsorption by the kidneys.