The enzyme pepsin is produced in the cells of the stomach but not in the cells of the small intestine. The small intestine produces a different enzyme, trypsin. The reason that the stomach and small intestine produce different enzymes is that the gene that codes for pepsin is

Correct Answer: B

Rationale: All cells have the same genes, but pepsin's gene is expressed (active) in stomach cells, not small intestine cells, due to tissue-specific regulation. It's not absent , mutated , or digested .

Correct Answer: A

Rationale: The appendix is attached to the cecum, part of the colon, making A correct.

Correct Answer: D

Rationale: Low stomach pH converts pepsinogen to active pepsin for protein digestion, making D correct.

Correct Answer: A

Rationale: The gallbladder stores bile for fat digestion, making A correct.

Correct Answer: B

Rationale: Villi, folds, and length increase digestive surface area, making B correct.