Norton Ghost backup

1.  During the Backup procedure I am asked to set the number of recovery points.  What is a recovery point, and what determines how many?

 

2.  Incremental Backup is, I presume, the updating of an existing backup.  If this is the case, will the incremental backup also include negative changes which may have occurred since the last backup, such as malware, erased programs and corrupted files?

If this is true, then surely it is better not to set automatic incremental backups.