having some problems with database MS SQL SERVER, 

and I would like to know if you could help me with some questions, thank you very much, I really appreciate your help.

• Where all data modifications are saved until committed or rolled back and then hardened to a data file.
• How many data filegroups does a MS SQL Server have
• SQL Server data pages are ______ in size.              
• How large is an SQL Server extent?
• How many pages make up an extent in MS SQL Server?
• How many bytes is the header in a data page?
• What does the data page in a data file do?
• What does the SGMA page in a data file do?
• What does the GAM page in a data file do?
• By default, SQL Server uses a technique called __________, which ensures that no changes are written to the data file before the necessary log record is written to the drive in a permanent form