You are presented with the quiz "What is formed when a sperm and egg unite in fertilization?" 

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 "sperm and eggs are cells known as gametes". 

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


 

        a diploid zygote   