You are presented with the quiz "What happens inside the single egg embedded inside the prothallus " 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "fertilization occurs when sperm swim to an egg inside an archegonium" and "each archegonium contains a single egg that is embedded in the prothallus". 

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


 

      fertilization occurs     