4. Which of the following statements about physical digestion and chemical digestion is correct?
A. Bile involves both physical and chemical digestion.
B. In the mouth cavity, carbohydrates undergo physical digestion only.
C. In both types of digestion, food substances are broken down into simpler molecules.
D. Physical digestion can enhance the efficiency of chemical digestion.

D

Explanation:

Example the action of teeth on food in the mouth increase surface area for salivary amylase to start digestion of starch

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.