How do symbiotic relationships affect the overall health of an ecosystem?

A) The relationships do not really matter in most ecosystems
B) The relationship helps organisms survive by providing nutrients that they may not be able to acquire.
C) The relationship gives the organisms an evolutionary advantage

B) The relationship helps organisms survive by providing nutrients that they may not be able to acquire.

Explanation:

Symbiosis is a close ecological relationship between the individuals of two (or more) different species. Sometimes a symbiotic relationship benefits both species, sometimes one species benefits at the other's expense, and in other cases neither species benefits.