Final answer:
Pulmonary arteries carry oxygen-poor blood away from the heart to the lungs for gas exchange.
Step-by-step explanation:
Pulmonary arteries are blood vessels that carry oxygen-poor blood away from the heart to the lungs. These arteries branch to supply blood to the pulmonary capillaries in the lungs, where gas exchange occurs.
The deoxygenated blood is then returned to the heart through the pulmonary veins.