Q

QuestionAnatomy and Physiology

A positive feedback loop is a process where the output of a system further increases the input, leading to an exponential increase in the process. In contrast, a negative feedback loop helps maintain equilibrium by reducing the output as the input increases.

Option A: Increased sunlight leads to more plant growth, which in turn leads to more oxygen production. This option describes a chain of cause-and-effect, but it does not necessarily represent a positive feedback loop. As plant growth and oxygen production increase, they do not further increase the initial input (sunlight). Therefore, option A is not an example of a positive feedback loop. Option B: A thermostat turns on the heater when the temperature drops below a set point. This option describes a negative feedback loop since the increased temperature (output) reduces the input (demand for heat) by turning off the heater. Therefore, option B is not an example of a positive feedback loop. Option C: Blood clotting occurs faster as platelets attract more platelets to the site of a wound. This option represents a positive feedback loop since the initial clotting process (input) triggers more platelets to gather, which accelerates clotting (output), leading to an exponential increase in the process. Option D: Sweating helps to cool the body down when it gets too hot. This option describes a negative feedback loop since sweating (output) reduces the body temperature (input), helping maintain equilibrium. Therefore, option D is not an example of a positive feedback loop.