( ( ( An organ ) ( of ( the body ) ) ) ( ( is ( ( ( a collection ) ( of ( different tissues ) ) ) ( which ( together ( perform ( a ( specific function ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT An) (NN organ)) (PP (IN of) (NP (DT the) (NN body)))) (VP (VBZ is) (NP (NP (DT a) (NN collection)) (PP (IN of) (NP (JJ different) (NNS tissues))) (SBAR (WHNP (WDT which)) (S (ADVP (RB together)) (VP (VBP perform) (NP (DT a) (JJ specific) (NN function))))))) (. .)))
An organ of the body is a collection of different tissues which together perform a specific function.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NP (JJ different) (NNS types)) (PP (IN of) (NP (NNS tissues)))) (VP (VBP work) (ADVP (RB together)) (S (VP (TO to) (VP (VB perform) (NP (DT a) (JJ unique) (NN function)))))))) (, ,) (NP (PRP they)) (VP (VBP form) (NP (NN organ))) (. .)))