L21A
45.1 Hormones and other signaling molecules bond to target receptors, triggering specific reponse pathway
45.2 Negative feedback and antagonistic gormone pairs are common features of the endocrine system
45.3 The endocrine and nervous systems act individually and together in regulating animal physiology
45.4 Endocrine glands respond to diverse stimuli in regulating metabolism, homeostasis, development, and behavior