Riddle For The Genius <br/><br/>”Challenge for all masterminds!!<br/><br/>? I'm am a 8 letter word<br/>? First 4 letters is a question<br/>? 2,3,4 protects our head<br/>? 5,6,7 is a liquid in tree<br/>? 7&8 are same letters.<br/><br/>?What am i?