( ( ( The ( sperm nucleus ) ) ( which ( is ( haploid ( -LRB- ( ( N -RRB- ) then ) ) ) ) ) ) ( ( fuses ( with ( ( the nucleus ) ( of ( ( the ovum ) ( which ( is ( ( haploid ( -LRB- ( N -RRB- ) ) ) ( to ( ( ( produce ( ( a ( diploid cell ) ) ( -LRB- ( 2N -RRB- ) ) ) ) or ) zygote ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN sperm) (NN nucleus)) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (VP (VBN haploid) (S (-LRB- -LRB-) (NP (NNP N)) (-RRB- -RRB-) (ADVP (RB then)))))))) (VP (VBZ fuses) (PP (IN with) (NP (NP (DT the) (NN nucleus)) (PP (IN of) (NP (NP (DT the) (NN ovum)) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (ADJP (JJ haploid) (PRN (-LRB- -LRB-) (NP (NNP N)) (-RRB- -RRB-)) (S (VP (TO to) (VP (VP (VB produce) (NP (NP (DT a) (JJ diploid) (NN cell)) (PRN (-LRB- -LRB-) (NP (CD 2N)) (-RRB- -RRB-)))) (CC or) (VP (VB zygote)))))))))))))) (. .)))
The sperm nucleus which is haploid (N) then fuses with the nucleus of the ovum which is haploid (N) to produce a diploid cell (2N) or zygote.
(ROOT (S (SBAR (IN While) (S (NP (NNS spermatogenesis)) (VP (VBZ produces) (NP (CD four) (JJ haploid) (NN sperm) (NNS cells))))) (, ,) (NP (NNS oogenesis)) (VP (VBZ produces) (NP (CD one) (JJ mature) (NN ovum))) (. .)))