Together, inhalation and exhalation are referred to as breathing. Inhalation is the process of breathing where air moves into the lungs through the nose and the mouth. This causes an increase in the volume of air in the lungs, meaning the pressure will decrease, thus the air then moves to the lungs. Exhalation on the other hand is the flow of the breath out of an organism, for example in humans it is the movement of air from the lungs out of the airways, to the external environment during breathing.
Answer:
Serotonin
Explanation:
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