( ( In humans ) ( , ( there ( ( are ( ( 23 pairs ) ( of ( chromosomes ( in ( a ( normal karotype ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (NNS humans))) (, ,) (NP (EX there)) (VP (VBP are) (NP (NP (CD 23) (NNS pairs)) (PP (IN of) (NP (NP (NNS chromosomes)) (PP (IN in) (NP (DT a) (JJ normal) (NN karotype))))))) (. .)))
In humans, there are 23 pairs of chromosomes in a normal karotype.
(ROOT (S (NP (NNS Humans)) (VP (VBP have) (NP (NP (CD 23) (JJ pairs) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))