You are presented with the quiz "what is found in proteins?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "nitrogen is found in proteins, nucleic acids, and chlorophyll" and "nitrogen, as a gas, is colorless, odorless, and a generally inert element". 

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


 

        a colorless, odorless gas   