Explanation:
Correct Answer: C. Rectum

To identify the terminal portion of the alimentary canal in a mammal, we need to understand what the alimentary canal is and how it’s structured.


What is the Alimentary Canal?

The alimentary canal, also known as the digestive tract, is the continuous tube through which food passes in the body. It includes:

1. Mouth
2. Pharynx
3. Oesophagus
4. Stomach
5. Small intestine (duodenum, jejunum, ileum)
6. Large intestine:
- Caecum
- Colon
- Rectum
- Anus

C. Rectum – Correct Answer

- The rectum is the last part of the large intestine.
- It serves as the storage site for feces before they are expelled through the anus, making it the terminal part of the alimentary canal.
- After the rectum, the anal canal leads to the anus, the external opening, but the rectum is considered the terminal portion of the internal canal system.

Other Options:

A. Oesophagus
- A tube connecting the mouth to the stomach. It’s closer to the start, not the end.

B. Stomach
- A muscular organ that digests food after it leaves the oesophagus. Not the end.

D. Colon
- A part of the large intestine that precedes the rectum. It absorbs water and salts, but is not the terminal part.

E. Appendix
- A small pouch attached to the caecum. It has no digestive role and is a vestigial structure.

Summary:
- The rectum is where undigested waste is stored before leaving the body.
- It’s the final internal segment of the digestive/alimentary canal.