( ( While ( we ( can ( ( go ( for ( extended periods ) ) ) ( without ( most nutrients ) ) ) ) ) ) ( , ( ( ( the limit ) ( without water ) ) ( ( is ( ( only ( a few ) ) days ) ) . ) ) ) )
(ROOT (S (SBAR (IN While) (S (NP (PRP we)) (VP (MD can) (VP (VB go) (PP (IN for) (NP (JJ extended) (NNS periods))) (PP (IN without) (NP (JJS most) (NNS nutrients))))))) (, ,) (NP (NP (DT the) (NN limit)) (PP (IN without) (NP (NN water)))) (VP (VBZ is) (NP (QP (RB only) (DT a) (JJ few)) (NNS days))) (. .)))
While we can go for extended periods without most nutrients, the limit without water is only a few days.
(ROOT (S (NP (JJS Most) (NNS people)) (VP (MD can) (VP (VB survive) (NP (QP (RB only) (DT a) (JJ few)) (NNS days)) (PP (IN without) (NP (NN water))))) (. .)))