( ( ( The strength ) ( of ( the ( secondary ( cell wall ) ) ) ) ) ( ( ( ( is ( due ( to ( ( the presence ) ( of ( ( ( lignin , ) ( a ( complex ( organic molecule ) ) ) ) , ) ) ) ) ) ) and ) ( ( gives plants ) ( enough ( rigidity ( to ( ( grow vertically ) ( -LRB- ( ( we ( will ( ( see ( plant cells ) ) ( in ( detail ( in class ) ) ) ) ) ) -RRB- ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN strength)) (PP (IN of) (NP (DT the) (JJ secondary) (NN cell) (NN wall)))) (VP (VP (VBZ is) (ADJP (JJ due) (PP (TO to) (NP (NP (DT the) (NN presence)) (PP (IN of) (NP (NP (NN lignin)) (, ,) (NP (DT a) (JJ complex) (JJ organic) (NN molecule)) (, ,))))))) (CC and) (VP (VBZ gives) (NP (NNS plants)) (NP (RB enough) (NN rigidity) (S (VP (TO to) (VP (VB grow) (ADVP (RB vertically)) (PRN (-LRB- -LRB-) (S (NP (PRP we)) (VP (MD will) (VP (VB see) (NP (NN plant) (NNS cells)) (PP (IN in) (NP (NP (NN detail)) (PP (IN in) (NP (NN class)))))))) (-RRB- -RRB-)))))))) (. .)))
The strength of the secondary cell wall is due to the presence of lignin, a complex organic molecule, and gives plants enough rigidity to grow vertically (we will see plant cells in detail in class).
(ROOT (S (NP (DT The) (JJ secondary) (NN wall)) (VP (VBZ contains) (NP (NP (NN lignin)) (, ,) (NP (NP (DT a) (JJ secondary) (NN cell) (NN component)) (PP (IN in) (NP (NN plant) (NNS cells))) (SBAR (WHNP (WDT that)) (S (VP (VBP have) (VP (VBN completed) (NP (NN cell) (NN growth/expansion))))))))) (. .)))