During the Cambrian Explosion,fossil Evidence Indicates a Rapid and Sudden

Multiple Choice

During the Cambrian explosion,fossil evidence indicates a rapid and sudden diversification of more complex animals.However,fossils of Ediacaran animals from 30 million years prior to this demonstrate that genes to produce complex animals had already existed.What could explain this?

A) a lack of gene expression due to lack of stress on the Cambrian species
B) changes in the environment that brought about selective adaptations and evolution during the Cambrian,repurposing some gene regions through differential regulation
C) changes that led to the innate ability of organisms during the Cambrian to mutate in response to environmental pressures or opportunities
D) a spatial pattern of organisms across the landscape during the Ediacaran that allowed adaptations and evolution