Raisins are a snack that is made from dehydrated grapes. While the sugar remains in the fruit, the water is removed, giving it its characteristic wrinkled appearance. A student is curious if she could rehydrate a raisin and get a grape again. She runs an experiment where she places a raisin in distilled water, another raisin in tap water, and a third raisin in salt water. The movement of water in and out of the raisin is called