What is the test for determining whether an act of negligence was the proximate cause of an injury?

"[I]t is a fundamental principle of tort law that there must be a legal duty owed to the person injured and a breach of that duty which is the proximate cause of the resulting injury." Ileto v. Glock, Inc., 349 F.3d 1191, 1206. Although the determination as to whether an act is the proximate cause of an injury is generally a question of fact, "it is a question of law where the facts are uncontroverted and only one deduction or inference may reasonably be drawn from those facts." Id.