( ( The ( digestive system ) ) ( ( starts ( with ( ( ( the mouth ) , ) ( where ( ( ( food and ) water ) ( enter ( our body ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ digestive) (NN system)) (VP (VBZ starts) (PP (IN with) (NP (NP (DT the) (NN mouth)) (, ,) (SBAR (WHADVP (WRB where)) (S (NP (NN food) (CC and) (NN water)) (VP (VBP enter) (NP (PRP$ our) (NN body)))))))) (. .)))
The digestive system starts with the mouth, where food and water enter our 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))))) (. .)))