( ( As ( they grow ) ) ( , ( trees ( ( compete ( for ( ( ( ( ( ( root space ) , ) sunlight ) , ) and ) water ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN As) (S (NP (PRP they)) (VP (VBP grow)))) (, ,) (NP (NNS trees)) (VP (VBP compete) (PP (IN for) (NP (NP (NN root) (NN space)) (, ,) (NP (NN sunlight)) (, ,) (CC and) (NP (NN water))))) (. .)))
As they grow, trees compete for root space, sunlight, and water.
(ROOT (S (NP (NNP Gravitropism)) (VP (VBZ ensures) (SBAR (SBAR (IN that) (S (NP (NNS roots)) (VP (VBP grow) (PP (IN into) (NP (DT the) (NN soil)))))) (CC and) (SBAR (IN that) (S (NP (NNS shoots)) (VP (VBP grow) (PP (IN toward) (NP (NN sunlight)))))))) (. .)))