What is the significance of a "responsive" document within a family of documents?

A "responsive" document within a family of documents is significant because it contains information that pertains directly to the issues at hand in a legal case. These documents are identified during the discovery process as relevant evidence that can support or undermine a party's arguments. The determination of whether a document is responsive depends on its content and how it relates to the specific claims or defenses in a case.

The other options do not accurately capture the role of a responsive document. The idea that it must be the only responsive document is not accurate, as multiple documents in a family can be found responsive. The first document reviewed does not inherently hold any additional significance apart from being the first in a review process. Lastly, while a responsive document may be part of a sequence followed by a non-responsive document, this is not a defining characteristic of what makes a document responsive in the context of a legal case. Thus, the primary significance revolves around its direct relevance to the case.