Oracle Database Discussions

Could you please clear my following doubts regarding SCN, Checkpoint and Commit

1. On Commit LGWR writes complete log buffer (committed and uncommitted data) to log files. Does LGWR update logfile headers with latest SCN number?
2. Does LGWR write SCN number to Control file as well?
3. On checkpoint dbwr writes latest scn to all the data files header, which means all the data files header will have same latest scn number irrespect to whether any data block have been changed dring this checkpoint or not. Right?
4. Does DBWR writes latest SCN to control file as well?
5. Like all datafiles always have same scn number in their header like that do all the logfiles header also have same scn in their header or different log files may have different scn numbers?
6. Does Control files stores only one value of SCN something like SCN=<> or multiple copies different for datafiles and redologfiles? If yes then how?
7. How can I read Control file scn numbers.

I know these are very basic questions but to become a successfull DBA one should always have clear ideas about these questions without any doubts. Please help...