Which of the following statements about inspiration is correct?

The correct statement about inspiration is that air enters the body, eventually arriving in an alveolus. During the process of inspiration, a contraction of the diaphragm and intercostal muscles creates a negative pressure within the thoracic cavity, allowing air to flow into the lungs. The air travels through the trachea and bronchi, eventually reaching the alveoli, which are tiny air sacs where gas exchange occurs. This process is essential for delivering oxygen to the bloodstream and removing carbon dioxide from the body.

The other statements do not accurately describe the process of inspiration. The first option implies a situation where breathing through the mouth or nose is not possible, which does not define inspiration but rather describes a pathological condition. The third statement incorrectly suggests that carbon dioxide is inhaled, when in fact, inspiration involves the intake of oxygen while carbon dioxide is removed during exhalation. Finally, the last option describes a device for measuring airflow, which is unrelated to the physiological process of inspiration itself.