(20 points) In the morning, you decide to make toasted bacon, lettuce, and tomato sandwich. Observe what happens in each stage of making the sandwich. Which parts involve only chemical changes happening? I. The first thing you do is cut two slices of bread.
II. Then you put the slices in the toaster to cook. When the toaster is done, it pops the III. warm brown toast. You cook the bacon in a frying pan you put bacon, lettuce, and tomato on the bread, trimming the sides.
IV. You can smell the old bread in the garbage going moldy.

Steps I and II
Steps II and III
Steps II and IV
Steps III and IV