This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
While doing sigmoidoscopy, if the rectum is inflated with gas, increased peristalsis is seen in 
Select and explain. 
A. Whole colon, B. Proximal colon, C. Distal colon, D. Whole intestine
C: Distal colon
Answer: C: Distal colon 
Explanation: Defecation reflex - When the rectum is distended, a reflex propulsive movement from descending colon to rectum occurs. Along with that, the internal anal sphincter relaxes. The same happens when the rectum is distended by gas.