( ( ( mouth - ) ( ( the ( first part ) ) ( of ( ( ( the ( digestive system ) ) , ) ( where ( food ( enters ( the body ) ) ) ) ) ) ) ) . )
(ROOT (NP (NP (NN mouth)) (: -) (NP (NP (DT the) (JJ first) (NN part)) (PP (IN of) (NP (NP (DT the) (JJ digestive) (NN system)) (, ,) (SBAR (WHADVP (WRB where)) (S (NP (NN food)) (VP (VBZ enters) (NP (DT the) (NN body)))))))) (. .)))
mouth - the first part of the digestive system, where food enters the body.
(ROOT (S (NP (DT The) (NN mouth)) (VP (VBZ is) (NP (DT the) (JJ first) (NN digestive) (NN organ)) (SBAR (IN that) (S (NP (NN food)) (VP (VBZ enters))))) (. .)))