Question

In a coloured diagram why do we generally
show the pulmonary artery in blue and
pulmonary vein in red colour ?​

Answer 1

because pulmonary artery carry deoxygenated blood or impure blood..

While pulmonary vein carry oxygenated or pure blood..

Answer 2

Explanation:

because pulmonary artery carries oxynated blood & pulmonary vein carries deoxygenated blood hence pa &pv are in blue & red clr