( ( Through photosynthesis ) ( , ( ( carbon dioxide ) ( ( is ( ( ( converted ( into ( ( sugar and ) oxygen ) ) ) , ) ( whereas ( ( through respiration ) ( , ( ( ( oxygen and ) sugar ) ( are ( ( converted back ) ( into ( carbon dioxide ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN Through) (NP (NN photosynthesis))) (, ,) (NP (NN carbon) (NN dioxide)) (VP (VBZ is) (VP (VBN converted) (PP (IN into) (NP (NN sugar) (CC and) (NN oxygen))) (, ,) (SBAR (IN whereas) (S (PP (IN through) (NP (NN respiration))) (, ,) (NP (NN oxygen) (CC and) (NN sugar)) (VP (VBP are) (VP (VBN converted) (PRT (RP back)) (PP (IN into) (NP (NN carbon) (NN dioxide))))))))) (. .)))
Through photosynthesis, carbon dioxide is converted into sugar and oxygen, whereas through respiration, oxygen and sugar are converted back into carbon dioxide.
(ROOT (S (S (NP (NNS Photosynthesis)) (VP (VBZ is) (VP (VBN described) (PP (IN by) (NP (DT this) (NN statement)))))) (: :) (S (NP (NP (NN carbon) (NN dioxide)) (CC and) (NP (NN water))) (VP (VBP are) (VP (VBN turned) (PP (IN into) (NP (NN sugar) (CC and) (NN oxygen)))))) (. .)))
Photosynthesis is described by this statement: carbon dioxide and water are turned into sugar and oxygen.