本题目来源于试卷: Interaction & Interdependence C.4 Chemical Signaling，类别为 IB生物学
[单选题]
Which of the following is an example:c+vm es.epy5 *pd 8e c:;-nqw)daavb of m*bbq -;.q ecxoe 1qh+a positive feedback mechanism?
A. Control of blood glucose concentration
B. Maintenance of body temperature in a homeotherm
C. Absorption of more water from the collecting duct as a result of ADH secretion
D. Increase of oxytocin bringing about further uterine contractions.
参考答案: D
本题详细解析:
D A positive feedback mechanism is a physiological process in which a response amplifies the initial stimulus, leading to an accelerated and often self-reinforcing outcome. The dilation of the cervix during childbirth stimulates the release of the hormone oxytocin. Oxytocin then brings about further uterine contractions, which brings about further cervix dilation. This is, therefore, an example of positive feedback, and Choice D is correct. A negative feedback mechanism is a regulatory mechanism in which a response counteracts and reverses the initial stimulus, maintaining stability and homeostasis in the system. Choices A, B, and C are all examples of negative feedback mechanisms.
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