The endorphins are the group of hormones that are secreted within the nervous system. These hormones triggers a positive feeling in the person.
The rods and cones are present in the retina. These photo-receptors are responsible for the perception of the colors and light by the eye of the person.
The thermoreceptors are responsible for the perception for the changes in the temperature of the stimuli. Therefore, the thermoreceptors will relay this information to the brain.
Hence, the correct answer is 'thermoreceptors'.
