A normal adult respiration rate is:

The normal adult respiration rate ranges from 10 to 20 breaths per minute during rest. This range is considered standard because it reflects adequate ventilation without any distress, aligning with physiological needs for oxygen intake and carbon dioxide removal in a healthy individual. The rate can vary based on several factors, including activity level, emotional state, and overall health, but for most adults at rest, the 10 to 20 breaths per minute range is what is typically expected.

In contrast, higher rates, such as those listed in the other choices, may indicate a condition known as tachypnea, which could be a response to a number of factors such as fever, anxiety, or potential respiratory distress. Understanding normal respiration rates is critical for assessing a patient's overall health and can serve as an early indicator for potential complications in a dental or medical setting.