Domain Name System
 1. In a _______ name space, a name is assigned to an address. A name in this space is a sequence of characters without structure.       
 2. In a _________name space, each name is made of several parts.       
 3. To have a hierarchical name space, a ______________ was designed.       
 4. In the DNS, the names are defined in ___________ structure       
 5. The root of the DNS tree is _______.       
 6. A full domain name is a sequence of labels separated by ________.       
 7. If a label is terminated by a null string, it is called a __________.       
 8. If a label is not terminated by a null string, it is called a __________.       
 9. . A _________ is a subtree of the domain name space.       
 10. What a server is responsible for or has authority over is called a _________.