IV. PLAINTIFFS MUST IDENTIFY THE TYPE OF “SUITABLE SEAT” THAT THEY COULD USE TO PERFORM THEIR JOB FULLY TO SHOW THAT THE “NATURE OF THE WORK REASONABLY PERMITS THE USE OF SEATS” Finally, as part of the inquiry into whether the nature of the work “reasonably permits” the use of seats under Section 14(A), a plaintiff must identify what type of “suitable seat” would allow the plaintiff to do her job fully, safely, and efficiently—to the extent such an option exists. Under California Evidence Code, section 500, “aparty has the burden of proofas to each fact the existence or nonexistence of which is essential to the claim for relief.” The existence of a suitable seat is essential to a claim under Section 14(A): if an employee could perform her job while seated in theory only, and it is unclear that a seat exists that could actually allow her to do so, then it cannot be concluded that the work “reasonably permits” the use ofa seat.