Answer the following question given this paragraph: 

The blood also carries hormones, which are chemical messenger molecules produced by organs of the endocrine system, through your body. Hormones are produced in one area of your body and have an effect on another area. To get to that other area, they must travel through your blood. An example is the hormone adrenaline, produced by the adrenal glands on top of the kidneys. Adrenaline has multiple effects on the heart (it quickens the heart rate), on muscles and on the airway.


Q: What system of the body is responsible for producing hormones?

 Choices:

- nervous system

- regulatory system

- homeostasis system

- endocrine system

A:
endocrine system
