Ferns and fungi often thrive in disrupted ecosystems. Scientists have observed an increase in fern and fungi fossils in the rocks directly above the Cretaceous–Paleogene boundary. What does this evidence suggest about the environmental conditions after the Chicxulub impact?

Ferns and fungi often spread when ecosystems are disrupted, such as after vegetation is damaged. Their increased fossils directly above the boundary suggest that the Chicxulub impact caused a major environmental change. This supports choice A, rather than the idea that conditions remained stable or improved rapidly.

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