( ( ( Photosynthesis and ) respiration ) ( ( ( ( play ( ( an ( important role ) ) ( in ( the ( carbon cycle ) ) ) ) ) and ) ( are ( at ( equilibrium ( with ( one another ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Photosynthesis) (CC and) (NNS respiration)) (VP (VP (VBP play) (NP (NP (DT an) (JJ important) (NN role)) (PP (IN in) (NP (DT the) (NN carbon) (NN cycle))))) (CC and) (VP (VBP are) (PP (IN at) (NP (NP (NN equilibrium)) (PP (IN with) (NP (CD one) (DT another))))))) (. .)))
Photosynthesis and respiration play an important role in the carbon cycle and are at equilibrium with one another.
(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))))) (. .)))