Answer: Large intestine.
Explanation:
There are some common misconception that all the bacteria can cause disease. They play an important role in the digestion of food.
The large intestines is the home for many different types of bacteria which helps in the absorption, excretion and catalysis of undigested food.
There are many types of prokaryotic and eukaryotic bacteria found in large intestine such as Methanogens, Bifidobacterium,Enterococcus, Clostridium et cetera.