What storage method is used to organize messages in Gmail, it is similar to a folder structure?

Which of the following technologies was developed to allow companies to use less-expensive storage while still maintaining the speed and redundancy required in a business environment?

A. RAID B. Tape Backup C. Load Balancing D. Clustering

To copy a tree, traverse it in __________ and add each data item visited to a new node.

a. inorder b. postorder c. reorder d. preorder