Which of the following is a symptom of shock?

A symptom of shock often includes rapid breathing and anxiety due to the body's response to a state of decreased blood flow or oxygen deprivation. When shock occurs, the body triggers a fight-or-flight response, leading to an increase in heart rate and respiratory rate as it attempts to compensate for the reduced circulation. This can result in symptoms such as rapid breathing (hyperventilation) and feelings of anxiety or panic as the brain senses a lack of adequate blood supply.

The other choices do not represent symptoms of shock. Improved vision and clarity would suggest adequate blood flow to the brain, which is contrary to what occurs during shock. Increased energy levels also contradict the body's reaction during shock, as energy levels typically decline due to inadequate oxygen and nutrient delivery. Lastly, a calm demeanor is not compatible with the physical and psychological stress response that occurs during shock, where individuals are often agitated or anxious due to the life-threatening circumstances they may be experiencing.