Active Directory Domains and Trusts:
Implementing trusts
Raising domain/forest functional levels
Adding user logon suffixes
Active Directory Sites and Services:
Configuring intrasite/intersite replication
Configuring global catalog
Creation of sites, site links, subnets.
Scheduling replication
Active Directory Users and Computers:
Managing users/groups
Managing computers.
Managing OUs
Managing Group Policy (Domain Level)
Managing Operations masters.
Raising domain functional level.
Domain controller security policy:
Set account, audit and password policies
Set user rights
Permissions or policies Pertains only to the DC where you set.
Domain security policy:
Set account, audit and password policies
Set user rights
Permissions or policies pertain to the DC as well as to all the domains within.