reading sql plan

dear all,

I have question about reading sql plan:

SQL> select * from employees e, departments d where e.department_id = d.department_id ;106 rows selected.Execution Plan----------------------------------------------------------Plan hash value: 1901596505--------------------------------------------------------------------------------------------------| Id  | Operation                    | Name              | Rows  | Bytes | Cost (%CPU)| Time     |--------------------------------------------------------------------------------------------------|   0 | SELECT STATEMENT             |                   |   106 |  9540 |     9  (12)| 00:00:01 ||   1 |  MERGE JOIN                  |                   |   106 |  9540 |     9  (12)| 00:00:01 ||   2 |   TABLE ACCESS BY INDEX ROWID| EMPLOYEES         |   107 |  7383 |     2   (0)| 00:00:01 ||   3 |    INDEX FULL SCAN           | EMP_DEPARTMENT_IX |   106 |       |     1   (0)| 00:00:01 ||*  4 |   SORT JOIN                  |                   |    27