Question

why is blood pumped to the lungs before it is pumped round the body​

Answer 1

for oxygenation blood is pumped to the lungs

Answer 2

Because when blood is pumped in whole body then the oxygen presents in the blood is being used by by the body cell for the production of necessary energy. So when all the oxygen is used up then this dioxygeneted blood is being sent to the lungs by the pulmonary artery to oxigenete the blood again in lungs then again collected by the heart through pulmonary vein and then resent it to the whole body and this process going on continuously.

IN ALVEOLI THE EXCHANGE OF OXYGEN AND CARBONDIOXIDE TAKES PLACE BETWEEN BLOOD.