( These ( generally ( ( ( ( rely ( on ( the ( oxidation-reduction cycling ) ) ) ) and ) ( ( play ( an ( important role ) ) ) ( in respiration ) ) ) . ) ) )
(ROOT (S (NP (DT These)) (ADVP (RB generally)) (VP (VP (VB rely) (PP (IN on) (NP (DT the) (JJ oxidation-reduction) (NN cycling)))) (CC and) (VP (VB play) (NP (DT an) (JJ important) (NN role)) (PP (IN in) (NP (NN respiration))))) (. .)))
These generally rely on the oxidation-reduction cycling and play an important role in respiration.
(ROOT (S (NP (NP (DT The) (NN structure)) (PP (IN of) (NP (NN mitochondrion)))) (VP (VBZ plays) (NP (NP (DT an) (JJ important) (NN role)) (PP (IN in) (NP (JJ aerobic) (NN respiration))))) (. .)))