The answer is the fight or flight response.
The fight or flight response is a survival mechanism in the body in the nervous system. It is how we respond to a stressful situation and is there to protect us from harm. Therefore it is not a risk factor for violence. It's our bodies natural way to protect us from violence.
The other choices are sadly all risk factors for violence.
During the resting heart, that is, the number of times the heart beats per minute while the body is relaxed and at rest does not change significantly with age; But with age, there are changes in the ability of the heart to increase its rate during exercise and other moments of stress. Younger hearts usually usually speed up more faster than older ones when challenged. The maximum heart rate, the highest heart rate one can achieve as measured by a cardiac stress test declines gradually in adults as they age. The cause of this is slowing down of the heart's pacemaker cells.
