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
Faecal mass is mainly derived from: March 2005 
Select and explain. 
A. Undigested food, B. Digested food, C. Intestinal secretions, D. intestinal flora
A: Undigested food
Answer: A: Undigested food 
Explanation: Ans. A: Undigested foodFaeces normally are about 3/4th water and 1/4th solid waste.Solid water is composed of:About 30% dead bacteria30% undigested roughage from the food and dried constituents of digestive juices.10-20% fat10-20% inorganic matter2-3% protein