So the stophagus, as we'll see in just a moment, is a tube that has a cylindrical shape. And the bolus, the fact that our chewing process creates this bolus is helpful because the bolus, the sphere of food, can easily move along Aristophagus. Now, let's move on to chemical digestion. So chemical digestion is the process by which our proteolytic enzymes actually break down and cleave the chemical bonds that hold our macromolecules together. So basically, these proteolytic enzymes catalyze the reaction known as hydrolysis. It's a catabolic reaction that breaks down our chemical bonds using water.