Answer:
sympathetic
Step-by-step explanation:
The sympathetic division of the autonomic nervous system is responsible for preparing the body under stress or emergency conditions such as being terrified by a large groundhog. The neurons of the sympathetic nervous system trigger an increase in heart rate, breathing rate to increase the oxygen supply needed by body cells under stress conditions.
Other physiological responses generated by the sympathetic nervous system under stress conditions are dilation of the pupil, increased blood pressure, etc. The sympathetic nervous system generates these responses by stimulating the release of stress hormone from the adrenal medulla. These responses are together called fight or flight response.