enrollment of a student and security

Can a student be enrolled in multiple classes?
Can this be used to grant reading and editing rights for the teachers and mentors at work?
A teacher must only see his own students and the teacher may only be able to adjust the evaluations he registered. But the student is enrolled in multiple classes

Hi Stacey, a student can only be enroled in a single Form Group (also known as a Roll Group in US English), but can be enrolled in multiple academic classes. Check out Admin > Timetable Admin > Manage Courses And Classes to set these up.

If you look at Admin > User Admin > Manage Permissions, you will see that there are various levels of access that you can give to teachers for Planner, Markbook, etc, in order to control who sees what.