Describe the two most important events in the history of animal life that occurred at the beginning and at the end of the paleozoic era. (2 pts) list and briefly outline the six different periods into which the paleozoic era is divided. (6 pts)

 multicelled animals went threw a dramatic expolision in diversity, almost all living animal phyla appeared within a few millions of years.an extraordinary diversification of marine animals, and ended about 252 million years ago with the end-Permian extinction, the greatest extinction event in Earth history. this is the second part of question the Cambrian, Ordovician, Silurian, Devonian, Carboniferous  

It is c commensalism

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