Passage: I was ready to change the look of my kitchen , so I decided to put up wallpaper . I went to a wallpaper store and took about two hours looking through catalogs to decide what I wanted . I ordered the wallpaper and when it arrived , I got to work .  Fortunately very few tools were necessary .  I had a pan to wet the wallpaper , which activated the glue on the back , and a brush to smooth it out .  First I set a plumb line , which involves a putting a light weight on a piece of string and putting the string in some chalk .  I put it in the center of the first wall I was going to paper to make sure I had a straight line .  Then I hung the first strip to be straight down the chalk line . I smoothed out the paper , then repeated with the next strip . I continued to do this until the entire room was papered . Question: What did they activate by putting the paper in water? Option1: glue on back Option2: The plumb line
glue on back