( It ( ( functions ( to ( initiate ( ( photosynthesis , ) ( ( a ( complex ( biochemical pathway ) ) ) ( ( in which ) ( ( solar energy ) ( is ( used ( to ( ( convert ( water ( and ( carbon dioxide ) ) ) ) ( to ( glucose ( and ( other carbohydrates ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ functions) (S (VP (TO to) (VP (VB initiate) (NP (NP (NN photosynthesis)) (, ,) (NP (NP (DT a) (JJ complex) (JJ biochemical) (NN pathway)) (SBAR (WHPP (IN in) (WHNP (WDT which))) (S (NP (JJ solar) (NN energy)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB convert) (NP (NN water) (CC and) (NN carbon) (NN dioxide)) (PP (TO to) (NP (NN glucose) (CC and) (JJ other) (NNS carbohydrates)))))))))))))))) (. .)))
It functions to initiate photosynthesis, a complex biochemical          pathway in which solar energy is used to convert water and carbon dioxide to         glucose and other carbohydrates.
(ROOT (S (NP (NNS Photosynthesis)) (VP (VBZ converts) (NP (NN carbon) (NN dioxide) (CC and) (NN water)) (PP (IN into) (NP (NN glucose)))) (. .)))