A student claims, "In order to maintain homeostasis, the body utilizes a variety of feedback mechanisms." Which of the following is an example of a positive feedback mechanism that could be used to support this statement? a. O2 levels in the blood increase and CO2 levels decrease. The brain tells the muscles of the diaphragm to inhale and exhale more rapidly. As O2 and CO2 levels returns to normal, the organism's breathing returns to normal.

b. During childbirth, the release of the hormone oxytocin stimulates uterine contractions, which in turn stimulates the release of more oxytocin.

c. An increase in body temperature causes humans to secrete a watery fluid in the form of perspiration. As the fluid evaporates from the skin removing the excess heat, the body stops perspiring.

d. High levels of glucose cause the pancreas to secrete more insulin. As glycogen forms from glucose, glucose levels decline and the pancreas stops secreting insulin.