You are presented with the quiz "what unites to form a diploid zygote?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "gametes then unite in fertilization and form a diploid zygote" and "collectively, the sperm and the ova are also referred to as gametes ". 

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


 

    sperm and ova       