A: To implement Temporal Validity(TV), 12c offers the option to have two date columns in that table which is having
TV enabled using the new clause Period For in the Create Table for the newly created tables or in the Alter Table for
the existing ones. The columns that are used can be defined while creating the table itself and will be used in the
Period For clause or you can skip having them in the table's definition in the case of which, the Period For clause
would be creating them internally.
E: ENABLE_AT_VALID_TIME Procedure
This procedure enables session level valid time flashback.

Explanation/Reference:
Explanation:
Multipartition maintenance enables adding, dropping, truncate, merge, split operations on multiple partitions.
A: Merge Multiple Partitions:
The new “ALTER TABLE … MERGE PARTITIONS ” help merge multiple partitions or subpartitions with a single statement. When merging multiple partitions, local and global index operations and semantics for inheritance of unspecified physical attributes are the same for merging two partitions.
B: Drop Multiple Partitions:
The new “ALTER TABLE … DROP PARTITIONS ” help drop multiple partitions or subpartitions with a single statement.
Example:
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SQL> ALTER TABLE Tab_tst1 DROP PARTITIONS
Tab_tst1_PART5, Tab_tst1_PART6, Tab_tst1_PART7;
Table altered
SQL>
Restrictions :
- You can’t drop all partitions of the table.
- If the table has a single partition, you will get the error: ORA-14083: cannot drop the only partition of a partitioned.

utlrp.sql and utlprp.sql
The utlrp.sql and utlprp.sql scripts are provided by Oracle to recompile all invalid objects in the database. They are typically run after major database changes such as upgrades or patches. They are located in the
$ORACLE_HOME/rdbms/admin directory and provide a wrapper on the UTL_RECOMP package. The utlrp.sql script simply calls the utlprp.sql script with a command line parameter of "0". The utlprp.sql accepts a single integer parameter that indicates the level of parallelism as follows.
0 - The level of parallelism is derived based on the CPU_COUNT parameter.
1 - The recompilation is run serially, one object at a time.
N - The recompilation is run in parallel with "N" number of threads.
Both scripts must be run as the SYS user, or another user with SYSDBA, to work correctly.