Answer:
E. coli within the large intestine. (Ans. B)
Step-by-step explanation:
Mutualism is ecological interaction and defined as a relationship in which both species get benefits. E. coli forms a symbiotic relationship (mutualism) with its host organism.
E. coli is minor microflora found in humans which helps in the absorption of vitamin K and some other important vitamins for the colon of the human body. E. coli get benefits from its host in the form of protection, proper nutrients for proper function and growth.
Mutualism involves the exchange of shelter, nutrients, protection and transportation.