( humans ( normally ( ( have ( ( 23 pairs ) ( of chromosomes ) ) ) . ) ) )
(ROOT (S (NP (NNS humans)) (ADVP (RB normally)) (VP (VBP have) (NP (NP (CD 23) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))
humans normally 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))))) (. .)))