Processes and stages
In the second process, the sperm enters the egg, and the zygote is formed.
It's difficult to imagine more than one process here. I think you mean:
In the second stage of the process, the sperm enters the egg, and the zygote is formed.
In English a process can occasionally be broken down into sub-processes, but normally we talk about these as stages.
Indonesians often make the same mistake with menu and items on a menu:
The second menu is sirloin steak.
The second item on the menu is sirloin steak.