What is the initial burden of proving material fact?

In order to meet this initial burden, "the defendant must present evidence that would preclude a reasonable trier of fact from finding that it was more likely than not that the material fact was true [citation], or the defendant must establish that an element of the claim cannot be established, by presenting evidence that the plaintiff 'does not possess and cannot reasonably obtain, needed evidence.' [Citation.]" (Kahn v. East Side Union High School Dist. (2003) 31 Cal.4th 990, 1003.)