WE INHALE ALL THE GASES AND TAKES ONLY OXYGEN THEN WHY IT IS SAID THAT WE EXHALE ONLY CARBON DIOXIDE
We inhale air that consists of gases like carbon dioxide, oxygen, nitrogen etc. Also we exhale same mixture of gases. It is said that we exhale carbon dioxide as it to specifically represent the gas which is produced during respiration as waste product and other gases are not produced during respiration.