b. After a forest fire, some species are able to move higher up in trees to find food and make nests.
Species diversity in an ecosystem provides different ecological niches, which allows species to have different ways of using resources such as food and shelter. In the case of a forest fire, some species may be able to survive and recover by adapting to the changed environment, such as by moving to higher levels in trees to find food and make nests. This is an example of how species diversity can help maintain the overall health and resilience of an ecosystem. The other options listed do not demonstrate a clear benefit of species diversity, and some even describe negative consequences of limited species diversity.