Answer:
Energy
Step-by-step explanation:
Energy is primarily responsible for all sorts of transformation of matter in and outside a body.
A food contains energy , that a plant has entrapped by converting solar energy into chemical energy. . When this food enters into the body, body tries to use this chemical energy for all its metabolic processes in the form of nutrients.
Hence, a food entering body through mouth is acted upon by various physical process such as churning, chewing, diluting, grinding etc. and chemical processes such as enzyme action , acid and base reaction to transform this chemical energy in food into usable form.