Where does the food that remains undigested as well as unabsorbed in the small intestine enter? 

The undigested food enters the colon, the first part of the large intestine after food has passed through the small intestine.

The large intestine acts as a storage area for undigested material and water, gradually moving it towards the rectum, where it is eliminated as faeces. 

Additional water and electrolytes are absorbed in the large intestine, further solidifying and reducing the volume of the faeces. 

A complex community of bacteria lives in the large intestine and ferments any remaining undigested carbohydrates, producing short-chain fatty acids and gas as byproducts.