Which of the following does not cause inspiration?

Inspiration occurs when there is a negative pressure in the lungs with respect to the atmospheric pressure. The contraction of the diaphragm and the external intercostal muscles results in an increase in the thoracic volume. The increase in the thoracic volume decreases the intrapulmonary pressure which causes the air to move from the atmosphere into the lungs. An increase in intrapulmonary pressure causes expiration.