So it's going to be obviously oxygen XD ....so that's one
Next, it's going to be carbon dioxide, since it has to exit the cell, because it is a waste product ...so that's two
Finally, it's also going to be something you drink everyday.
*whispers* it's water XD because of osmosis
So recap:
1) Oxygen 2) Carbon Dioxide 3) Water
hope that helps!! :D