_____ are chemical messengers that are released by cells and transported in the bloodstream to alter the activities of specific cells in other tissues.

_____ are chemical messengers that are released by cells and transported in the bloodstream to alter the activities of specific cells in other tissues.

_____ are chemical messengers that are released by cells and transported in the bloodstream to alter the activities of specific cells in other tissues.









A) Hormones
B) Neuropeptides
C) Neurotransmitters
D) Humoral antibodies
E) Antigens











Answer: A