What are the structures of the pulmonary circuit, and in what order does blood run through them?

Blood in the pulmonary circuit leaves the right side of the heart, especially the right ventricle, through the pulmonary artery and travels to the lungs. After picking up oxygen, it returns through the pulmonary veins. Thus the sequence is the right atrium and ventricle, pulmonary artery, lungs, and pulmonary veins, as in choice C.

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