( ( In humans ) ( there ( ( are ( ( ( ( 46 chromosomes ) , ) or ) ( ( 23 homologous ) pairs ) ) ) . ) ) )
(ROOT (S (PP (IN In) (NP (NNS humans))) (NP (EX there)) (VP (VBP are) (NP (NP (CD 46) (NNS chromosomes)) (, ,) (CC or) (NP (QP (CD 23) (CD homologous)) (NNS pairs)))) (. .)))
In humans there are 46 chromosomes, or 23 homologous pairs.
(ROOT (S (NP (NNS Humans)) (VP (VBP have) (NP (NP (CD 23) (JJ pairs) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))