( ( The ( cell wall ) ) ( ( is ( ( a ( distinguishing ( plant ( cell part ) ) ) ) ( which ( ( is not ) ( ( ( present ( in animals ) ) and ) ( mainly ( responsible ( for ( ( imparting rigidity ) ( to ( the cells ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN cell) (NN wall)) (VP (VBZ is) (NP (NP (DT a) (JJ distinguishing) (NN plant) (NN cell) (NN part)) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (RB not) (ADJP (ADJP (JJ present) (PP (IN in) (NP (NNS animals)))) (CC and) (ADJP (RB mainly) (JJ responsible) (PP (IN for) (S (VP (VBG imparting) (NP (NN rigidity)) (PP (TO to) (NP (DT the) (NNS cells))))))))))))) (. .)))
The cell wall is a distinguishing plant cell part which is not present in animals and mainly responsible for imparting rigidity to the cells.
(ROOT (S (NP (DT A) (NN cell) (NN wall)) (VP (VBZ is) (RB not) (ADJP (JJ present) (PP (IN in) (NP (NN animal) (NNS cells))))) (. .)))