Answer :
Final answer:
Pioneer species and climax communities differ in their occurrence in succession, size and complexity, and species composition.
Explanation:
Pioneer species and climax communities differ in several ways:
Pioneer species occur only in primary succession, while climax communities can occur in both primary and secondary succession.
Pioneer species tend to be small and simple, while climax communities tend to be larger and more complex.
Pioneer species include only one or two species, while climax communities include many species.