The normal flora on your skin competes with pathogens for space and food. the relationship between you and your normal flora is an example of a symbiotic relationship?
a. commensal
b. mutualistic
c. parasitic
d. this is not a symbiotic relationship

b. Mutualistic

Explanation:

The symbiotic relationships are defined by the interacition between two species, In the mutualistic symbiotic relationship both of the organisms get benefits from the interaction. in the case of the normal flora in the skin as they compete with pathogens for space and food they prevent this patogens to go in the human skin, and they get food from the skin, so as they give protecttion and obtain food, both of the organisms are getting benefits and because of this:

The relationship between you and your normal flora is an example of a mutualistic symbiotic relationship.