1. How heap sort works? (re-heap up for insertion/construction, and re-heap down for deletion/soring)

2. The basic idea of merge sort, why it is chosen as the external sorting algorithm for file operations? Seek time for each step?

3. What is AVL tree?

4. explain with examples AVL tree operation (tree insertion, single rotation, and double rotation)

5. what is paged binary tree? What are the pros and cons?

6. What is B-tree? What are the differences between data structure B-tree, and file structure B-tree?

7. explain B-tree insertion, search, and deletion

8. what is the Time complexity of operating on B-tree

provide full answers to these question with example and explanation, please