which plays both a role in physical and chemical digestion?\nteeth\nsaliva\ngall bladder\nvilli

Brief Explanations:

Teeth physically break down food by chewing (mastication). Saliva contains enzymes like amylase that start the chemical - breakdown of carbohydrates. The gall bladder stores and releases bile which is involved in chemical digestion of fats, but not physical digestion. Villi are mainly for absorption, not physical or chemical digestion in the way the question asks. Saliva has both physical (moistening food) and chemical (enzymatic action) roles in digestion.

Answer:

saliva