( ( ( ( ( The duodenum ) ( is ( ( the ( first part ) ) ( of ( the ( small intestine ) ) ) ) ) ) and ) ( ( most ( of ( the ( chemical digestion ) ) ) ) ( occurs here ) ) ) . )
(ROOT (S (S (NP (DT The) (NN duodenum)) (VP (VBZ is) (NP (NP (DT the) (JJ first) (NN part)) (PP (IN of) (NP (DT the) (JJ small) (NN intestine)))))) (CC and) (S (NP (NP (JJS most)) (PP (IN of) (NP (DT the) (NN chemical) (NN digestion)))) (VP (VBZ occurs) (ADVP (RB here)))) (. .)))
The duodenum is the first part of the small intestine and most of the chemical digestion occurs here.
(ROOT (S (NP (JJS Most) (NNS digestion)) (VP (VBZ is) (VP (VBN completed) (PP (IN in) (NP (DT the) (NN duodenum))))) (. .)))