What functionality does a group provide in ArcGIS Online?

A group in ArcGIS Online primarily serves to enable sharing and collaboration among users. When users join a group, they can access shared content, which fosters collaborative work on projects and tasks relevant to the group's objectives. Groups can be tailored for various purposes, such as project teams or specific community interests, making it easier to manage and distribute resources, like maps and data layers, among members.

This ability to share resources is essential for effective teamwork and project collaboration, allowing members to view, edit, and contribute content in a unified space. Through settings that control group visibility and access, administrators can ensure that only designated users can participate, streamlining workflows and enhancing cooperation on shared initiatives.

The other options address functionalities that are not central to the specific role of groups within ArcGIS Online. While third-party applications can be hosted in ArcGIS for various purposes, this is unrelated to the group functionality. Storage space is generally managed at the account level rather than through group membership, and while user account visibility may be impacted by group membership settings, it is not a primary function of the group itself. Thus, the collaborative aspect of groups is accurately highlighted as the core feature that enhances teamwork within the ArcGIS Online environment.