Answer
If no mutualisms existed between fungi and other organisms, land plants would be much less successful due to their having many fewer mineral nutrients available, and lichens would not have been able to help make soils in the first place. There would also be fewer species of creatures like ants which interact with fungi to their benefit (as in the case of leaf-cutting ants).
Work Step by Step
Review Concept 34.5, making a list of benefits to non-fungi that come from interacting with fungi, and then simply summarize the list in a few sentences.