( This ( ( is ( because ( ( too ( many variables ) ) ( ( ( affect ( tulip growth ) ) ( in ( ( the ( second year ) ) ( for ( the experiment ) ) ) ) ) ( to ( be dependable ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ is) (SBAR (IN because) (S (NP (RB too) (JJ many) (NNS variables)) (VP (VBP affect) (NP (NN tulip) (NN growth)) (PP (IN in) (NP (NP (DT the) (JJ second) (NN year)) (PP (IN for) (NP (DT the) (NN experiment))))) (S (VP (TO to) (VP (VB be) (ADJP (JJ dependable))))))))) (. .)))
This is because too many variables affect tulip growth in the second year for the experiment to be dependable.
(ROOT (S (NP (JJ Dependent) (NN variable)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (PP (IN for) (NP (NP (DT the) (VBN affected) (NN factor)) (PP (IN in) (NP (DT an) (NN experiment))))))) (. .)))