You are presented with the quiz "what requires penetration?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "fertilization occurs when a sperm and an egg fuse to form a diploid zygote" and "penetration is when the sperm and egg meet and the sperm makes it way into the egg cytoplasm". 

So, what's the best answer to the question?


 

        fertilization   