In which part of alimentary canal does absorption of water, simple sugars and alcohol takes place?

The food mixes thoroughly with the acidic gastric juice of the stomach by the churning movements of its muscular wall. What do we call the food then?

Trypsinogen is an inactive enzyme of pancreatic juice. An enzyme, enterokinase, activates it. Which tissue/ cells secrete this enzyme?/ How is it activated?

Name the enzymes involved in the breakdown of nucleotides into sugars and bases?

Define digestion in one sentence.