Final answer:
The mass extinction that ended the Triassic and led to the Jurassic Period allowed dinosaurs to evolve and outperform other Archosaurs.
Step-by-step explanation:
The geologic event that allowed the dinosaurs to evolve and eventually outperform other Archosaurs was the mass extinction that ended the Triassic and paved the way for a dinosaur takeover in the Jurassic Period. This extinction event created a favorable environment for dinosaurs to flourish and dominate. Additionally, during the Jurassic, the earliest birds evolved from reptile ancestors, and all the major groups of mammals evolved, although they were still small in size. Flowering plants and new insects also appeared during this time.