SQL Server Full Backup Internally

Q. What are the steps SQL Server performs internally at the time of FULL backup?
Ans. SQL Server follow the below steps once you execute the BACKUP command
1.Backup Process will lock the database and block all the transaction
2.Place a mark in the transaction log
3.Release the database lock
4.Extract all the pages in the data files and write them to the backup device
5.Lock the database and block all the transactions
6.Place a mark in the transaction log
7.Release the database lock
8.Extract the portion of the log between the marks and append it to backup

Q. Which operations do not allowed during the full backup?
1.Adding and removing database files
2.Shrinking the database