Question

which occurs during digestion?
the mouth only allows for physical digestion.
the mouth only allows for chemical digestion.
chemical digestion prepares the food for physical digestion.
physical digestion prepares the food for chemical digestion.

Explanation:

• Physical digestion in the mouth (e.g., chewing) breaks food into smaller pieces. This increases the surface area of the food.
• With a larger surface area, digestive enzymes (which are involved in chemical digestion) can act more effectively on the food. So physical digestion prepares the food for chemical digestion.
• The mouth is involved in both physical (chewing) and chemical (salivary amylase starts starch digestion) digestion. So the first two options are incorrect.
• Chemical digestion does not prepare food for physical digestion in the way that physical digestion prepares for chemical. Chemical digestion acts on the already physically - broken - down food (in most cases).

Answer:

Physical digestion prepares the food for chemical digestion.