c) melatoninMELATONIN= primary function is regulation of the circadian cycle (rhythum of sleep/wakefulness)INSULIN= helps regulate the amount of glucose in the body- w/o insulin, the body is unable to convert blood sugar into energyTESTOSTERONE= the main hormone produced by the testes; responsible for male sex characteristicsEPINEPHRINE= AKA ADRENALINE; quickens/strengthens the heartbeat & dilates the bronchioles; secreted when the body senses danger