Complete question:
Question: Some of the nerve endings in the skin are sensitive to changes in temperature. They are part of a negative feedback mechanism regulating body temperature. These nerve endings represent a(n) ________ in the negative feedback mechanism.
a) effector
b) control center
c) homeostatic balance or "ideal" value
d) receptor
Answer:
d) receptor
Explanation:
Receptors are the cells or the structures present in organisms that sense any change in internal or external conditions such as temperature, light intensity, pressure, touch, etc. The receptors are activated when they sense a particular change. These changes are called stimuli.
In the given example, nerve endings sense the changes in temperature. This means that they are serving as receptors for "temperature" stimulus. Change in temperature conditions would activate nerve endings which in turn would send the sensory information to a control center.
