Question

exam lesson name: introduction to human anatomy and physiology
exam number 700794rr
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question 13 of 20 :
select the best answer for the question

1. which of the following is an example of a positive feedback mechanism?

a. the kidneys retain more water if the organisms water level is low.
b. insulin causes cells to absorb glucose.
c. during childbirth, the baby’s head pushing on the cervix encourages uterine contractions.
d. body temperature is increased if skeletal muscles move quickly and cause a person to shiver.
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Explanation:

To determine the example of positive feedback, we analyze each option:

• Option A: Kidneys retaining water is a negative feedback (restores water balance, counteracts low water level).
• Option B: Insulin reducing blood glucose is negative feedback (counteracts high glucose).
• Option C: During childbirth, the baby’s head pushing on the cervix stimulates more uterine contractions, which further push the head, amplifying the process—this is positive feedback (reinforces the stimulus).
• Option D: Shivering to increase temperature is negative feedback (counteracts low temperature).

Answer:

C. During childbirth, the baby’s head pushing on the cervix encourages uterine contractions.