How do lungs get rid of all the co2 they’ve picked up from the blood? And why do you think the body’s cells need oxygen

Your lungs get rid of co2 when you breathe out (exhale). the oxygen you breathe to get energy from the food you eat.
hopefully this kinda helps!

Carbon dioxide (CO2) is a waste product of cellular metabolism. You get rid of it when you breathe out (exhale). This gas is transported in the opposite direction to oxygen: It passes from the bloodstream – across the lining of the air sacs – into the lungs and out into the open.

Then it is june the conclusion to the second sentence is just restating "if it is june then it is summer"