( ( A ( human zygote ) ) ( ( has ( ( 23 pair ) ( of chromosomes ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ human) (NN zygote)) (VP (VBZ has) (NP (NP (CD 23) (NN pair)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))
A human zygote has 23 pair of chromosomes.
(ROOT (S (NP (NNS Humans)) (VP (VBP have) (NP (NP (CD 23) (JJ pairs) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))