Which term refers to describing why or how something occurs?

The term "Explanation" is specifically used in a literary and analytical context to describe why or how something occurs. It involves providing details and reasoning that clarify the underlying causes or principles behind a particular phenomenon, event, or idea. When one offers an explanation, they are engaging in the process of breaking down complex information into understandable terms and answering questions of causality or mechanism.

In contrast, the other options serve different functions: Assertion refers to a statement or claim made without providing evidence; Clarification aims at making something less confusing or more comprehensible, but not necessarily explaining the cause; Elaboration involves adding detail to a concept or argument but does not specifically address the reasons behind occurrences. Thus, "Explanation" is the most accurate term for the act of detailing why or how something happens.