Which of the following can increase respiration?

Excitement can significantly increase respiration due to the body's response to heightened emotional states or physical activity. When a person is excited, the sympathetic nervous system is activated, leading to an increase in heart rate and respiratory rate as the body prepares for increased physical demands. This is part of the "fight or flight" response, where the body requires more oxygen to cope with perceived challenges or thrills, and this demand for oxygen translates to increased breathing.

In contrast, options such as sleep typically result in decreased respiration as the body enters a restorative phase; drugs can vary in their effects, with some potentially increasing respiratory rate while others may decrease it; and depressants generally slow down bodily functions, including respiration. Understanding these physiological responses is crucial in recognizing how various states or substances can affect breathing rates.