( ( ( xylem and ) phloem ) ( ( are ( ( ( complex tissues ) ( -LRB- ( ( ( back ( to this ) ) later ) -RRB- ) ) ) ( There ( are ( ( three ( basic ( cell types ) ) ) ( in plants ) ) ) ) ) ) . ) )
(ROOT (S (NP (NN xylem) (CC and) (NN phloem)) (VP (VBP are) (NP (NP (JJ complex) (NNS tissues)) (PRN (-LRB- -LRB-) (FRAG (ADVP (RB back) (PP (TO to) (NP (DT this)))) (ADVP (RB later))) (-RRB- -RRB-)) (SBAR (S (NP (EX There)) (VP (VBP are) (NP (NP (CD three) (JJ basic) (NN cell) (NNS types)) (PP (IN in) (NP (NNS plants))))))))) (. .)))
xylem and phloem are complex tissues (back to this later) There are three basic cell types in plants.
(ROOT (S (NP (NNP Modern) (NNS plants)) (VP (VBP have) (NP (NP (CD three) (NNS types)) (PP (IN of) (NP (JJ major) (NNS tissues))))) (. .)))