Question 4 of 11
How to play
the game
    
    Show Diagrams
 O2  +    H2      H2O  
O-O H-H H-O-H  
O-O H-H H-O-H  
O-O H-H H-O-H  
O-O H-H H-O-H  
O-O H-H H-O-H  
O-O H-H H-O-H  
O-O H-H H-O-H