Chapter 1 homework: 1. What column(s) make up the primary key of the GRADE table? 2. How many foreign keys does the ENROLLMENT table have? 3. Explain recursive/self-referencing relationship using the relevant table and column(s) from the STUDENT schema. 4. Explain the relationship(s) the GRADE TYPE WEIGHT table has to other table(s). 5. Can a foreign key column in a table accept any data value? Explain using the relevant tables from the STUDENT schema.