Question

The main function of the colon (large intestine) of mammals is to
A. Temporarily store of excretory products
B. Absorb water from undigested food
C. Absorb digested food
D. Digest cellulose
E. Produce enzymes used in other parts of the alimentary canal

Answer 1

Hint: Large intestine is larger in diameter than small intestine, But smaller in length. It does not secrete any digestive enzyme; but it absorbs water, salt, vitamins and minerals. Also, it stores undigested food till it passes to anus.

Complete answer:
Large intestine consists of three parts: cecum, colon and rectum.
Cecum lies within the junction of the small intestine; it has a small projection called an appendix. In humans, Appendix helps in fighting infection.
Colon makes up the major part of the large intestine constituting three parts ascending colon, transverse colon and descending colon. Descending colon becomes S-shaped at the end forming a sigmoid colon. The main function of the colon is to reabsorb the nutrients and fluid from the food and pass on the waste material to rectum.
Rectum connects the colon with anus which is approximately 8-inch in size. It receives waste material from the colon and passes to anus. The terminal part of rectum is called as anal canal.

So, the main function of the colon is to absorb water from undigested food. Correct answer here is option B.

Note:
The main function of the large intestine is to absorb salt and water and elimination of faeces. Many bacteria are present inside the colon which help in digesting small amounts of cellulose and other substances. These bacteria also synthesize VitK, VitB.