15. During inspiration, A. alveolar pressure exceeds atmospheric pressure. B. transpulmonary pressure increases. C. the diaphragm relaxes. D. intrapulmonary pressure is less than atmospheric pressure

D

Intrapulmonary pressure is less than atmospheric pressure

Explanation:

During Inspiration air Rushes in and fills the lungs when the diaphragm and the muscles between the ribs contracts, while the diaphragm pulls downward the muscles between the ribs pull upward this increases the size of the Thoracic cavity and decreases the intra pulmonary pressure and causes air to rush in to the lungs.

the answer is c.the valence of the atoms combine .

answer///carbon;