universe,End-Cretaceous, Ecosystems on the Brink

The final stages of the Cretaceous, roughly 66 to 67 million times agone
 , saw terrestrial ecosystems at their most intricate and connected state, yet decreasingly vulnerable to environmental disquiet. By this period, angiosperms had come the dominant foliage type across utmost tableland timbers, floodplains, and littoral plains, shaping both the structure and dynamics of terrestrial ecosystems. Gymnosperms survived in defined territories, frequently in highland or cooler microclimates, while ferns,