The escherichia coli bacteria that live in your intestine and break down food are an example of which type of interaction?
a. competition
b. mutualism
c. parasitism
d. predation

In this scenario, E.coli is living in our intestines, which means we are providing them with a place to live and nutrients to survive. It is also stated that they help us break down some foods. 
so as you can see, we benefit them, and they benefit us. 
Based on this, after defining all of your options, you will find your answer. 

the glands which are associated with each description is given below:

pancreas - is an endocrine and exocrine gland that secretes juices with enzymes for digestion. salivary glands- with protection and digestion in the mouth. liver- secretes bile for digestion.   lachrymal glands - secrete tears to moisten eyes and protect them from particles and infection.   sweat gland -regulates water, salt, and temperature. oil glands - to form a protective barrier on the skin.   goblet cells - secrete mucus for protection.