The part of the alimentary canal where food is finally digested is the small intestine.
Explanation: While digestion starts in the mouth and continues in the stomach, the majority of digestion and absorption of nutrients occurs in the small intestine.
Why other options are incorrect:
a) Stomach:
The stomach plays a crucial role in protein digestion but the small intestine completes the process.
b) Mouth cavity:
Digestion begins in the mouth with the breakdown of carbohydrates through saliva.
c) Large intestine:
The large intestine primarily absorbs water and electrolytes from undigested material, not completing digestion.