You are presented with the quiz "What are simple units which are neither prokaryotes nor eukaryotes?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "viruses are not cells at all, so they are neither prokaryotes nor eukaryotes" and "viruses Viruses Viruses are simple units which invade cells". 

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


 

  viruses         