What does an iron lung do?
a. it served as a lung for animals stricken with polio as part of the testing of cures
b. it was an air-tight iron tank designed to exert a push-pull motion on the chest - basically forcing patient's diaphrams to breathe.
c. it was the earliest design of the heart-lung machine and assisted polio patients who were in a coma
d. it fortified people's lungs with iron
e. none of these