1) TRUE ,The main problem of primary indexes when inserting, updating or deleting, Since the records are physically ordered in the data file, records often need to be moved around to make room for new records. In the case of deletions, the severity depends on the implementation; closing the gaps in the blocks is often an expensive operation, but using delete markers and periodic reorganization reduces this overhead.
2)TRUE ,as we know clustering index has two field,one field for clustering field and another for disk block pointer
3)FALSE ,becoz a primary index and a clustered index cannot exist on a table at the same time. This is because both of these index types physically order the records. More than one primary index or several clustered indexes also cannot exist because there may only be at most one physical ordering field per file.
