The answer of this is part c
<span>developing a new way to extract a particular protein from tissue samples</span>
Gas exchange is the delivery of oxygen from the lungs to the bloodstream, and the elimination of carbon dioxide from the bloodstream to the lungs. It occurs from the lungs between the alveoli and a network and a bunch of tiny blood vessels called capillaries, which is located in the walls of the alveoli.
~Sorry if I typed some stuff wrong, I'm eating a popsicle while typing this~