During childbirth, physical stretching of the uterus causes the release of a hormone that results in stronger, more frequent contractions. these contraction increase the stretching of the uterus. this is an example of a) a positive feedback loop, because the hormone increases uterine stretching. b) a negative feedback loop, because the hormone increases uterine stretching. c) a positive feedback loop, because a condition in the body causes an increase in a hormone. d) a negative feedback loop, because a condition in the body causes an increase in a hormone.