Which physiological change occurs during inhalation?

During inhalation, the diaphragm and intercostal muscles contract, which leads to an increase in the volume of the thoracic cavity. As the volume of the lungs increases, the pressure inside the lungs decreases relative to the atmospheric pressure outside the body. This pressure differential causes air to flow into the lungs to equalize the pressure. This principle is explained by Boyle's Law, which states that at constant temperature, the pressure of a gas decreases as its volume increases. Therefore, the correct answer aligns with this understanding of the mechanics of inhalation, highlighting the increase in lung volume and the corresponding decrease in pressure that facilitates breathing.