( ( Food digestion ) ( mainly ( ( occurs ( in ( the ( small intestine ) ) ) ) . ) ) )
(ROOT (S (NP (NNP Food) (NNP digestion)) (ADVP (RB mainly)) (VP (VBZ occurs) (PP (IN in) (NP (DT the) (JJ small) (NN intestine)))) (. .)))
Food digestion mainly occurs in the small intestine.
(ROOT (S (PP (IN In) (NP (DT the) (NN body))) (, ,) (NP (NN chemical) (NN digestion)) (ADVP (RB mainly)) (VP (VBZ takes) (NP (NP (NN place)) (PP (IN in) (NP (DT the) (JJ small) (NN intestine))))) (. .)))
In the body, chemical digestion mainly takes place in the small intestine.