1. display the first and last name, and mark for the student who their marks less than 50.
2. display the first and last name, and mark for the student who their marks more than 50displaytheresult in ascending order of mark.
 
3. use sub queries to display the subject name who all students passed their subject.
 
4. display the student's first name, last name, subject name, and mark with the mark of more than 70.

Use subqueries to display the subject name and subject number who have more than one student enrolled in