Johnny left a glass of milk on his bedside table for a week, and it spoiled. at the end of the week, the glass contained a yellow liquid with lumpy white chunks and a terrible odor. what can be concluded? a. the milk has undergone a physical change. b. the mass of the milk before the change is less than the mass of the milk after the change. c. milk only forms iconic bonds. or d. the milk has undergone a chemical change