Answer:
The relationship between E.coli and human is a parasitism that is "symbiotic relationship"(a kind of parasitism ) .
Step-by-step explanation:
Parasitism
It refers to the" relation in which one organism lives in or on the body of other organism to fulfill its nutritional requirement" .
The one who lives is parasite and other on whom it lives is Host .
In other words we can say ,that parasite gets an advantage and Host faces a kind of harm .
For example : Lice is an parasite and is often present in human head where it harms human by sucking blood .
But ,this is not true in all cases.
For example : in case of E.coli bacteria and human .
This bacteria lives in the intestine of humans but in this case both humans and bacteria is benefited. This parasitic relationship changes to symbiosis that is where both the partners are mutually benefited .
Like in this case, bacteria help humans by producing certain vitamins that are essential for humans and in return it gets nutrition and place to live inside the human's body .