( ( The ( immune system ) ) ( ( is ( ( a ( complex network ) ) ( of ( organs ( containing ( cells ( that ( ( ( ( recognize ( foreign substances ) ) ( in ( the body ) ) ) and ) ( destroy them ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ immune) (NN system)) (VP (VBZ is) (NP (NP (DT a) (JJ complex) (NN network)) (PP (IN of) (NP (NP (NNS organs)) (VP (VBG containing) (NP (NP (NNS cells)) (SBAR (WHNP (WDT that)) (S (VP (VP (VB recognize) (NP (JJ foreign) (NNS substances)) (PP (IN in) (NP (DT the) (NN body)))) (CC and) (VP (VB destroy) (NP (PRP them)))))))))))) (. .)))
The immune system is a complex network of organs containing cells that recognize foreign substances in the body and destroy them.
(ROOT (S (NP (DT The) (JJ immune) (NN system)) (ADVP (RB typically)) (VP (VP (VBZ recognizes)) (, ,) (VP (VBZ attacks)) (, ,) (CC and) (VP (VBZ destroys) (NP (NP (JJ foreign) (NNS cells) (CC or) (NNS substances)) (SBAR (WHNP (WDT that)) (S (VP (MD may) (VP (VB cause) (NP (NN disease))))))))) (. .)))
The immune system typically recognizes, attacks, and destroys foreign cells or substances that may cause disease.