( ( Starch digestion ) ( ( begins ( in ( ( the mouth ) ( when ( ( the molecules ) ( are ( ( chewed and ) ( ( broken up ) ( by ( the teeth ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Starch) (NN digestion)) (VP (VBZ begins) (PP (IN in) (NP (NP (DT the) (NN mouth)) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NNS molecules)) (VP (VBP are) (VP (VP (VBN chewed)) (CC and) (VP (VBN broken) (PRT (RP up)) (PP (IN by) (NP (DT the) (NNS teeth))))))))))) (. .)))
Starch digestion begins in the mouth when the molecules are chewed and broken up by the teeth.
(ROOT (S (NP (NNP Digestion)) (VP (VBZ begins) (PP (IN in) (NP (DT the) (NN mouth)))) (. .)))