( ( ( ( ( Fertilization ( triggers ( Meiosis II ) ) ) , ) and ) ( then ( ( the ( sperm nucleus ) ) ( unites ( with ( the ( resulting ( egg nucleus ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Fertilization)) (VP (VBZ triggers) (NP (NNP Meiosis) (NNP II)))) (, ,) (CC and) (S (ADVP (RB then)) (NP (DT the) (NN sperm) (NN nucleus)) (VP (VBZ unites) (PP (IN with) (NP (DT the) (VBG resulting) (NN egg) (NN nucleus))))) (. .)))
Fertilization triggers Meiosis II, and then the sperm nucleus unites with the resulting egg nucleus.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT a) (NN sperm)) (VP (VBZ penetrates) (NP (DT the) (NN egg))))) (, ,) (NP (PRP it)) (VP (VBZ triggers) (NP (DT the) (NN egg) (S (VP (TO to) (VP (VB complete) (NP (NNS meiosis))))))) (. .)))