Class 11 NEET Biology Body Fluids and Circulation

(b) : The pulmonary artery carries deoxygenated blood from the heart to the lungs while the pulmonary vein carries oxygenated blood from the lungs to the heart. A pulmonary artery has a smaller lumen and thicker walls as compared to a pulmonary vein. Thus, the correct answer is 'Its wall is thick.'