You are presented with the quiz "ats and proteins can be used for energy by the cells of what?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "glucose is used for energy by the cells of most organisms" and "after hours of no glucose ingestion, fats and proteins can be used for energy". 

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


 

       most organisms    