The impact theory of mass extinction for Earth's biota has not yet received either its final confirmation or complete rejection and remains a working hypothesis, often explaining what is not explicable by other theories. Among all the five mass extinctions recorded in the stratigraphic annals of the Earth, only the most recent K-T boundary (transition from the Cretaceous to the Tertiary period) has been proved to be associated with the impact (or impacts). In this paper, we used the data of the Earths Impact Structures catalog (developed by the author) in evaluating how the known impact events are related to these major five boundaries. The given data show that the impact factor, unlike alternatives, has a sufficient evidence of its mandatory participation in the biota mass extinction.