Symbiotic relationship between human/E. coli

E. coli is a bacteria prevalent in human intestines. It produces vitamins, like Vitamin K, for humans, and in turn, we provide it shelter and the nourishment necessary for it to survive. This demonstrates a symbiotic relationship because two species, humans and E. coli, are living in direct and intimate contact with each other. More specifically, this demonstrates mutualism because both species are being benefited from this relationship.