Thanks Jon for very informative feedback, and based on this I made some adjustments to my model now

I try to be more business minded so any one can understand what relationship entities have among each others and also removed some to avoid any complexity.

Thanks

1- A student has contact information and one address (I got rid of multiple addresses to be more simple)
2- A student can belong to many groups 
3- A student can have many postings
4- A student can enroll to many course enrollments
5- A course enrollment can have many course offering
6- A course offering has one instructor
7- A course can have many course offering (course reuse) 
8- An instructor can have many postings
9- A course can belong to many groups
10- A course has one subject
11- A course belong to one program
12- A course can have many exam, assignments and quiz

I hope this make sense and I think its getting close to finish with the help and feedback of Jon and classmates.

Thanks 

Shafiq