( However ( , ( ( in ( considering ( ( both ( the response ) ) ( of ( ( ( plants ( to ( rising ( atmospheric ( CO ( 2 concentration ) ) ) ) ) ) and ) ( ( the ( carbon balance ) ) ( of plants ) ) ) ) ) ) ) ( , ( ( ( the process ) ( of photosynthesis ) ) ( ( is central ) . ) ) ) ) ) )
(ROOT (S (ADVP (RB However)) (, ,) (PP (IN in) (S (VP (VBG considering) (NP (NP (PDT both) (DT the) (NN response)) (PP (IN of) (NP (NP (NP (NNS plants)) (PP (TO to) (S (VP (VBG rising) (NP (JJ atmospheric) (JJ CO) (CD 2) (NN concentration)))))) (CC and) (NP (NP (DT the) (NN carbon) (NN balance)) (PP (IN of) (NP (NNS plants)))))))))) (, ,) (NP (NP (DT the) (NN process)) (PP (IN of) (NP (NN photosynthesis)))) (VP (VBZ is) (ADJP (JJ central))) (. .)))
However, in considering both the response of plants to rising atmospheric CO 2 concentration and the carbon balance of plants, the process of photosynthesis is central.
(ROOT (S (NP (NP (DT The) (NN process)) (ADJP (JJ responsible) (PP (IN for) (NP (NP (DT the) (NN presence)) (PP (IN of) (NP (NP (NN oxygen)) (PP (IN in) (NP (PRP$ our) (NN atmosphere))))))))) (VP (VBZ is) (NP (NN photosynthesis))) (. .)))