( They ( ( work ( by ( ( ( ( ( taking oxygen ) ( from ( ( the air ) ( we ( breathe in ) ) ) ) ) and ) then ) ( ( exchanging it ) ( for ( ( ( carbon dioxide ) , ) ( ( a ( deadly ( waste product ) ) ) ( made ( by ( ( the cells ) ( of ( the body ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBP work) (PP (IN by) (S (VP (VP (VBG taking) (NP (NN oxygen)) (PP (IN from) (NP (NP (DT the) (NN air)) (SBAR (S (NP (PRP we)) (VP (VB breathe) (PRT (RP in)))))))) (CC and) (ADVP (RB then)) (VP (VBG exchanging) (NP (PRP it)) (PP (IN for) (NP (NP (NN carbon) (NN dioxide)) (, ,) (NP (NP (DT a) (JJ deadly) (NN waste) (NN product)) (VP (VBN made) (PP (IN by) (NP (NP (DT the) (NNS cells)) (PP (IN of) (NP (DT the) (NN body)))))))))))))) (. .)))
They work by taking oxygen from the air we breathe in and then exchanging it for carbon dioxide, a deadly waste product made by the cells of the body.
(ROOT (S (PP (IN In) (NP (DT the) (NN body))) (, ,) (S (NP (NN oxygen)) (VP (VBZ is) (VP (VBN used) (PP (IN by) (NP (NP (NNS cells)) (PP (IN of) (NP (NP (DT the) (NN body) (POS 's)) (NNS tissues)))))))) (CC and) (S (NP (NN carbon) (NN dioxide)) (VP (VBZ is) (VP (VBN produced) (PP (IN as) (NP (DT a) (NN waste) (NN product)))))) (. .)))