What is the airflow direction into the lungs during the inspiration stage?

During the inspiration stage, the diaphragm and external intercostal muscles contract, expanding the thoracic cavity and creating a negative pressure within the lungs relative to atmospheric pressure. This pressure difference causes air to rush inside the lungs, following the natural flow from areas of higher pressure to areas of lower pressure. As a result, the correct choice highlights this process of air entering the lungs during inhalation. Understanding this mechanism is crucial for comprehending how respiratory systems function, as the flow of air is essential for the exchange of oxygen and carbon dioxide in the body.