( ( Of ( ( all ( the ( ( tissues and ) organs ) ) ) ( in ( the ( human body ) ) ) ) ) ( ( the ( nervous system ) ) ( ( is ( ( ( the ( most ( ( intricate and ) complex ) ) ) , ) ( consisting ( of ( ( more ( ( than one ) trillion ) ) neurons ) ) ) ) ) . ) ) )
(ROOT (S (PP (IN Of) (NP (NP (PDT all) (DT the) (NNS tissues) (CC and) (NNS organs)) (PP (IN in) (NP (DT the) (JJ human) (NN body))))) (NP (DT the) (JJ nervous) (NN system)) (VP (VBZ is) (NP (NP (DT the) (ADJP (RBS most) (JJ intricate) (CC and) (JJ complex))) (, ,) (VP (VBG consisting) (PP (IN of) (NP (QP (JJR more) (IN than) (CD one) (CD trillion)) (NNS neurons)))))) (. .)))
Of all the tissues and organs in the human body the nervous system is the most intricate and complex, consisting of more than one trillion neurons.
(ROOT (S (NP (DT The) (NN sequence) (NN cell) (CD →) (NN tissue) (CD →) (NN organ) (CD →) (NN organ) (NN system)) (VP (VBZ identifies) (NP (NP (DT the) (NNS levels)) (PP (IN of) (NP (NP (NN organization)) (PP (IN of) (NP (NP (NN body) (NNS structures)) (PP (IN in) (NP (DT a) (NN human)))))))) (PP (IN from) (NP (NP (JJS simplest)) (PP (TO to) (NP (JJS most) (NN complex)))))) (. .)))
The sequence cell → tissue → organ → organ system identifies the levels of organization of body structures in a human from simplest to most complex.