Which statement correctly describes the roles of the pulmonary artery and pulmonary vein ?
1
The pulmonary artery carries oxygen-rich blood; the pulmonary vein carries oxygen-poor blood.
2
Both the pulmonary artery and pulmonary vein carry oxygen-rich blood
3
The pulmonary artery carries oxygen-poor blood; the pulmonary vein carries oxygen-rich blood.
4
Both the pulmonary artery and pulmonary vein carry oxygen-poor blood