Platelets, which have negatively charged cell membranes, adhere to the positively charged surface of a torn blood vessel.As they do so, they release substances that attract more platelets to the damaged area and change the charge on their cell membranes to positive.More platelets adhere to the damaged are a.The cycle repeats until the damaged area is sealed.What sort of feedback loop is formed, and why
A)positive-feedback loop: the response reinforces the initial change
B)negative-feedback loop: the response opposes the initial stimulus
C)negative-feedback loop: having too many platelets in one area blocks blood flow
D)positive-feedback loop: the response prevents a person from haemorrhaging to death

Question

Quizplus · Accepted Answer

The situation described in the passage is an example of a positive-feedback loop, as the response (release of substances that attract more platelets and change their charge) reinforces the initial change (platelets adhering to the damaged area). This leads to more platelets being attracted to the area and further sealing the damage, eventually stopping the bleeding.

Platelets, Which Have Negatively Charged Cell Membranes, Adhere to the Positively