Where do certain symbiotic microorganisms normally occur in human body?

Step-by-step solution

Caecum is the proximal part of large intestine. It is connected to colon (the largest part of large intestine). Colon does not contain digestive gland but harbours a number of microorganisms which feed on indigestible matter, some of them are symbiotic. They produce vitamin-K and vitamin-B complex.