Final answer:
Inhalation is the result of stimulation by nerve impulses generated in the respiratory center when they arrive at the muscles involved in inspiration.
Step-by-step explanation:
Inspiration is the result of stimulation by nerve impulses generated in the respiratory center when they arrive at the muscles involved in inspiration.
During inspiration, two main muscle groups are activated: the diaphragm and the external intercostal muscles. When the diaphragm contracts and moves downward, it increases the volume of the thoracic cavity. Simultaneously, the external intercostal muscles contract and move the ribs upward and outward, further expanding the thoracic cavity. This increase in volume creates a lower pressure inside the lungs, causing air to flow into the respiratory tract.
Therefore, the correct answer is B) Inhalation.