Mass extinctions have occurred five times in Earth’s history. The end Permian and Cretaceous extinctions were responsible for removing a large percentage of organisms from the planet. How do these extinctions contribute to the biodiversity we see today? A. Species that have gone extinct are able to re-evolve from the ancestors that survived the extinction. B. Species that remain after the extinction are able to radiate, new adaptations arise, and these produce the diversity seen today. C. Species that remain after the extinction are unable to speciate, therefore the number of species on Earth today is lower than just before either extinction. D. Species that remain after the extinction represent all of the lineages that were present before the extinction event, therefore diversity of lineages is not changed by extinction.