A university consists of several colleges. Within each college there are several departments. Each department may run a number of courses. All teaching staff is attached to departments, each staff member belonging to a unique department. (Note: see how many meanings you can assign to this ambiguous sentence). Every course is composed of sub-courses. Some sub-courses are part of more than one course. Staff may teach on many sub-courses and each sub-course may be taught by a number of staff. Draw an entity-relationship model for this example. Show both minimum and maximum cardinalities. Put a question mark where the degree is not clear from the text. Don't assume anything; rather, write a list of questions you would have to find answers to in order to complete the model.