Final answer:
The type of organization that maintains the zones for a TLD is called the Registry. Registrars provide domain name registration services, while IANA coordinates unique identifiers for the internet.
Step-by-step explanation:
The type of organization that maintains the zones for a top level domain (TLD) such as .ORG is called the Registry. The registry is responsible for managing the database of domain names within a specific TLD. They maintain the zone files that contain the necessary information for resolving domain names to IP addresses.
The Registrar is a separate entity that interacts directly with domain name owners. They provide domain name registration services to individuals and organizations. Registrars are responsible for collecting registration fees, managing contact information, and updating the registry with new domain name registrations.
The International Assigned Numbers Authority (IANA) is responsible for coordinating the assignment of unique identifiers for the internet. While they play an important role in managing the overall domain name system, maintaining the zones for TLDs is not their specific responsibility.