Which of the following is not an example of one of cannon’s postulates regarding the mechanisms that maintain physiological homeostasis? a. a neuron that fires action potentials at an intermediate rate at rest, but increases its rate when its stimulus changes@ no, this is an example of tonic levels of activity in a control system, which is one of cannon’s postulates. b. the sympathetic versus the parasympathetic nervous systems@ no, the sympathetic and parasympathetic divisions of the autonomic nervous system are a good example of antagonistic control, which is one of cannon’s postulates. c. epinephrine dilates some blood vessels and constricts others@ no, this is an example of the postulate that hormones can have different effects on different tissues. d. cervical stretch stimulates the release of oxytocin and uterine contractions@ yes, this is an example of a positive feedback loop, which does not maintain homeostasis, and therefore cannot be one of cannon’s postulates. e. neurons increase the heart rate in response to decreased blood pressure@ no, this is an example of control of homeostasis of blood pressure by neurons.