Because Visio does not explicitly show associative entities, it is not clear in Figure 2-22 which entity types are associative. List the associative entities in this figure. Why are there so many associative entities in Figure 2-22?

SALESPERSON DOES BUSINESS IN TERRITORY PK Salesperson ID Serves + PK Territory ID Salesporson Name Salesperson Telephone Salesperson Fax Territory Name CUSTOMER PRODUCT LINE PK Customer ID PK Product Line ID Customer Name Customer Address Product Line Name Customer Postal Code Submits Includes ORDER PK Order ID Order Date PRODUCT ORDER LINE PK Product ID Product Description Product Finish Ordered Quantity Product Standard Price VENDOR USES PRODUCED IN PK Vendor ID Vendor Name Goes Into Quantity Vendor Address RAW MATERIAL WORK CENTER PK Material ID SUPPLIES PK Work Center ID Material Name Material Standard Cost Work Center Location Supply Unit Price Unit Of Measure Is Supervised By EMPLOYEE WORKS IN Supervises OPK Employee ID HAS SKILL SKILL Employee Name Employee Address PK Skill