You are presented with the quiz "Name one kind of a protein that some viruses have inside their phospholid envelope?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "some viruses have an envelope of phospholipids and proteins" and "intrinsic proteins are embedded in the phospholipid". 

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


 

       intrinsic    