What catalyzes digestion?

amylace

Physical digestion is, basically, "mashing." The food is ground up (by the teeth), mashed into a paste (by the stomach), and so forth. It's mixed with other foods in the process, but no new molecules...

your butt

The word 'catalyze' means change by catalysis or cause to catalyze

chemical digestion is breaking down with saliva, and mechanical digestion is chewing...(break down with chew!):):P