Correct Answer:
Explanation/Reference:
. A forest is a single instance of Active Directory.
. Leaf objects are objects that have no child objects, and are the most basic component of the logical structure.
. Domains are logical directory components that you create to manage the administrative requirements of your organization. The logical structure is based on the administrative requirements of an organization, such as the delegation of administrative authority, and operational requirements, such as the need to control replication.
Domains can also be defined as:
Containers within a forest
Units of Policy
Units of Replication
Authentication and Authorization Boundaries
Units of Trust
Reference: What Are Domains and Forests?
https://technet.microsoft.com/en-us/library/cc759073%28v=ws.10%29.aspx#w2k3tr_logic_what_yokf