In a process called diffusion, oxygen moves from the alveoli to the blood through the capillaries (tiny blood vessels) lining the alveolar walls. Once in the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells.
The answer to this question would be: paranasal sinus.
There are a few sinuses near the face area. The sinus can be classified based on the bone that makes then to sinus maxillae, ethmoid, sphenoid and frontalis. This structure frequently gets infected causing sinusitis. Sinusitis patient can complain pain or feel the sinus got filled with some liquid.
The answer is D. 4 because its after perception
