Oracle DBA storage questions

Q. 1: Oracle immediately re-uses the space assigned to row-directory portion of the data block once you delete the corresponding rows.
　　
1. True
2. False
　　
2
　　　
　　 Q. 2: Which of the following three portions of a data block are collectively called as Overhead.
　　
1. table directory, row directory and row data
2. data block header, table diretory and free space
3. table directory, row directory and data blcok header
4. data block header, row data and row header
　　
3
　　
　　 Q. 3: Which portion of the data block contains table or index data
　　
1. table directory
2. row directory
3. overhead
4. row data
　　
4
　　
　　 Q. 4: What are the two space management parameters for controling the use of free space in a data block
　　
1. INITIAL and NEXT
2. PCTFREE and PCTUSED
3. TABLESPACE and STORAGE
4. free space cannot be controlled at block level
　　
2
　　　　
　　 Q. 5: The maximum number of transactions that a block can support is
　　
100.
2. 255
3. 1000
4. unlimited
　　　
2
　　　
　　 Q. 6: what is PCTFREE
　　
1. A space management parameter which sets aside that much percentage of memory in the data block for future update of existing rows.
2. A space management parameter which determines the minimum percentage of a block that can be used for row data plus overhead.
3. A space management parameter which tells Oracle that the block is available for inserts after the percentage of used memory falls below certain percentage.
4. all of them
　　　
1
　　
　　 Q. 7: What is the default value of NEXT parameter
　　
1. 1 block
2. 2 blocks
3. 5 blocks
4. 100 blocks
　　
3
　　
　　 Q. 8: Which parameter reserves the more space for future updates
　　
1. high PCTINCREASE
2. high PCTFREE
3. high INITIAL
4. high PCTUSED
　　　
2
　　
　　 Q. 9: PCTFREE and PCTUSED together shocould not exceed
　　
100.
2. 50
3.25
4. 10
　　
1
　　
　　 Q. 10: Row migration is a result
　　
1. not enough space in a block for new rows.
2. not enough memory for sorts
3. not enough space for updates in the current block
4. all of them
　　
3
　　　
　　 Q. 11: Frequent deallocation of extents result in
　　
1. truncated segments
2. block fragmentation
3. truncated tablespaces
4. tablespace fragmentation
　　
4
　　
　 Q. 13: Row migration is a result
　　
1. high PCTFREE
2. low PCTFREE
3. high PCTUSED
4. low PCTUSED
　　　
2
　　
　 Q. 12: Which background process coalesce the fragmented space
　　
1. SMON
2. PMON
3. DBWR
4. LGWR
　　
1