Final answer:
The question discusses the legal conditions under which an adult can be legally declared missing, which is a topic related to social studies and typically handled within the law enforcement and legal fields.
Step-by-step explanation:
The question provided appears to relate to conditions under which a missing person, over the age of 21, can be entered into a missing person database. This situation typically involves law enforcement and the legal standards for declaring someone as missing. These standards are developed based on social policies and state regulations, which might require the documentation that supports the person's status as missing, such as evidence that the individual's disappearance is not voluntary or could potentially be in danger.
The provided excerpts discuss different contexts: the presence of remains in a grave, a plea for emancipation reflecting historical context, and a mention of Jewish burial practices. These seem to be examples from archaeological findings and historical documents, which are used to study the past and understand the social and legal conditions of different periods.