You are presented with the quiz "What occurs when haploid gametes unite?" 

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 "haploid gametes unite to form diploid zygote". 

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


 

     fertilization      