( ( ( ( The ( fertilised egg ) ) or ) zygote ) ( then ( ( divides ( ( billions ( of times ) ) ( to ( produce ( ( more cells ) ( that ( ( will eventually ) ( ( ( form you ) , ) ( all ( having ( the ( same ( 46 chromosomes ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (NP (DT The) (JJ fertilised) (NN egg)) (CC or) (NP (NN zygote))) (ADVP (RB then)) (VP (VBZ divides) (S (NP (QP (NNS billions) (IN of) (NNS times))) (VP (TO to) (VP (VB produce) (NP (NP (JJR more) (NNS cells)) (SBAR (WHNP (WDT that)) (S (VP (MD will) (ADVP (RB eventually)) (VP (VB form) (NP (PRP you)) (, ,) (S (RB all) (VP (VBG having) (NP (DT the) (JJ same) (CD 46) (NNS chromosomes))))))))))))) (. .)))
The fertilised egg or zygote then divides billions of times to produce more cells that will eventually form you, all having the same 46 chromosomes.
(ROOT (S (PP (IN In) (NP (NNS humans))) (, ,) (NP (DT a) (NN zygote)) (VP (VBZ has) (NP (CD 46) (NNS chromosomes))) (. .)))