( ( A ( single gene ) ) ( ( contains ( thousands ( of rungs ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ single) (NN gene)) (VP (VBZ contains) (NP (NP (NNS thousands)) (PP (IN of) (NP (NNS rungs))))) (. .)))
A single gene contains thousands of rungs.
(ROOT (S (NP (DT A) (JJ single) (JJ human) (NN body) (NN cell)) (ADVP (RB typically)) (VP (VBZ contains) (NP (NP (NNS thousands)) (PP (IN of) (NP (NNS genes))))) (. .)))
A single human body cell typically contains thousands of genes.