Why does chewing food speed up digestion?
A) Bacteria in the food are killed.
B) Food is mixed with protease.
C) The surface area of the food is increased.
D) The taste of food is improved.
▶️ Answer/Explanation
Ans: C
Chewing food breaks it into smaller pieces, increasing its surface area (Option C). This allows digestive enzymes to act more efficiently, speeding up chemical digestion.
Option A is incorrect because chewing does not kill bacteria (stomach acid does). Option B is wrong because protease mixes with food later in digestion. Option D is irrelevant to digestion speed.
Which row about bile is correct?
▶️ Answer/Explanation
Ans: D
Bile is produced in the liver and stored in the gallbladder. It emulsifies fats (mechanical digestion) and neutralizes stomach acid, but it does not contain enzymes (chemical digestion).
The correct row (D) states that bile emulsifies fats and is alkaline, aligning with its role in fat breakdown and pH adjustment. Other rows incorrectly attribute enzyme content or misidentify its production site.