A thing, document, or testimony that bears on the truth or falsity of an assertion made in litigation is called______.

The concept described in the question refers to "evidence," which encompasses any material or testimony that supports or contradicts an assertion in a legal context. In litigation, evidence is critical as it is the foundation upon which cases are built and evaluated. It can include a wide range of items such as documents, witness testimonies, tangible objects, or expert opinions that help establish the truth of the claims being made.

Understanding the role of evidence in legal proceedings is paramount, as it is the means by which parties substantiate their arguments, allowing either side to present their case effectively. In contrast to the other options, which pertain to different legal concepts or standards, evidence specifically refers to the information that is utilized to analyze and adjudicate the truth of claims in court.