And this is known as chewing, or mastication. Now, this chewing process, the chewing of food, actually transforms our food into a spherical mass we call the bolus. And this shape of the bolus basically allows the movement of the spherical bolus along our cylinder known as Aristophagus. 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.