What is true of the Cambrian explosion?
A) There are no fossils in geological strata that are older than the Cambrian explosion.
B) Only the fossils of microorganisms are found in geological strata older than the Cambrian explosion.
C) The Cambrian explosion is evidence for the instantaneous creation of life on Earth.
D) The Cambrian explosion marks the appearance of filter-feeding animals in the fossil record.
E) Recent evidence supports the contention that the Cambrian explosion may not have been as "explosive" as was once thought.
