You are presented with the quiz "Reptiles are a class of tetrapod vertebrates that produce eggs with a what?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "reptiles are a class of tetrapod vertebrates that produce amniotic eggs" and "all reptiles produce eggs with a waterproof shell full of amniotic fluid". 

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


 

       waterproof shell    