In histological specimen it is seen oocyte at moment of fertilization by spermatozoon. What is main result of this process?

In histological specimen it is seen oocyte at moment of fertilization by spermatozoon. What is main result of this process?

1.  Acrosomal reaction


2.  Oocyte completes meiosis


3.  Penetration of oolemma


4.  Cortical reaction


5.  *Zygote formation