Detailed Instructions: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
Problem:Most, if not all, of the extant animal phyla today evolved during the cambrian period, yet many of mass extinctions devastating events have taken place since then.
Solution:
Most, if not all, of the extant animal phyla today evolved during the cambrian period, yet many of what devastating events have taken place since then?