The structural and functional unit of the alimentary canal is the

Correct Answer: C

Rationale: Villi are the small intestine's functional units, maximizing absorption. 'Villi,' is correct, per histology (e.g., Ross), with enterocytes for digestion and uptake. 'Mucosa,' is a layer containing villi. 'Muscularis,' aids motility. 'Serosa,' is the outer layer. Villi's absorptive role makes C the precise answer.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.