Answer:
The limbic system is a system of structures that includes the amygdala. This system has been implicated in emotion behavior.
Explanation: Hello! I answered your question but know how to explain. :)
The correct answer is the suprachiasmatic nucleus of the hypothalamus. The suprachiasmatic nucleus, as the name suggests, is the part of the hypothalamus located in right above above the optic chiasm. The main function of the suprachiasmatic nucleus is mainly responsible for the circadian rhythm of the body therefore the physiological activity on daily cycles.
B. the intensity o stimulus and the observer's criteria.