( ( Human cells ) ( ( have ( ( 23 pairs ) ( of chromosomes ) ) ) . ) )
(ROOT (S (NP (NNP Human) (NNS cells)) (VP (VBP have) (NP (NP (CD 23) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))
Human cells have 23 pairs of chromosomes.
(ROOT (S (NP (NNS Humans)) (VP (VBP have) (NP (NP (CD 23) (JJ pairs) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))