( ORGANS ( ( are ( ( discrete structures ) ( that ( consist ( of ( ( ( at least ) 2 ) ( tissues types ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS ORGANS)) (VP (VBP are) (NP (NP (JJ discrete) (NNS structures)) (SBAR (WHNP (WDT that)) (S (VP (VBP consist) (PP (IN of) (NP (QP (IN at) (JJS least) (CD 2)) (NNS tissues) (NNS types)))))))) (. .)))
ORGANS are discrete structures that consist of at least 2 tissues types.
(ROOT (S (NP (DT A) (PRN (-LRB- -LRB-) (NP (NN n)) (-RRB- -RRB-)) (NN organ)) (VP (VBZ is) (NP (NP (DT a) (NN structure)) (SBAR (WHNP (WDT that)) (S (VP (VBZ is) (VP (VBN composed) (PP (IN of) (NP (NP (QP (CD one) (CC or) (JJR more)) (NNS types)) (PP (IN of) (NP (NNS tissues))))))))))) (. .)))
A(n) organ is a structure that is composed of one or more types of tissues.