In Conservatorship of Geiger (1992) 3 Cal.App.4th 127, the court set forth the appropriate standard of review, stating, "Normally we are bound by the lower court's determination of facts based upon substantial evidence and reasonable inferences drawn from those facts. If different inferences can be drawn from undisputed facts, we must accept the lower court's inference. However, if the court's inference is rebutted by clear, positive and uncontradicted evidence it may not be supported. " The Geiger court goes on to note that we are not bound by the trial court's finding on ultimate issues, where the question is one of law derived from undisputed facts. However, "legal conclusions are only valid if supported by a trial court's finding of fact, which in turn must be supported by the evidence before the court, and we therefore review both in this case." (Conservatorship of Geiger, supra, 3 Cal. App. 4th at p. 133.) In Geiger, upon undisputed facts, the trial court had determined that the proponents of the presumption had not met their burden of proving all the requirements of section 12401, specifically that they had not shown the absence of a satisfactory explanation for the individual's disappearance. The appellate court, applying the correct standard of review, found that this determination was "fully supported by substantial evidence in the record," and properly "declined to substitute its opinion for any inferences made from the evidence by that court." Having properly applied the substantial evidence standard of review to the trial court's determination of facts, including inferences to be drawn from undisputed facts disclosed from the evidence, the appellate court affirmed the trial court's decision. (Conservatorship of Geiger, supra, 3 Cal. App. 4th at p. 136.)