What are AWS Organizations?
AWS Organizations is an account management service that enables you to consolidate multiple AWS accounts into an organization that you create and centrally manage.
What are the major advantages of consolidated billing?
Consolidated Billing is an advantage of AWS Organizations. The three major advantages are:
What are two forms of best practices for a root account with AWS organizations?
How can I enable/disable AWS services for either the organizational level or on individual accounts?
Enable/Disable AWS services using Service Control Policies (SCPs) either on Organizational Units or on individual accounts
How can you “merge” one AWS Organization into another?
(Needs Source)