I. (25 points) Draw an Entity-Relationship (ER) diagram that describes the following business environment.

The Memphis Zoo wants to create a information system to keep track of its animals and the support personnel and supplies that maintain them. Each animal has a unique animal number, as well as a name (e.g. Dumbo, Simba, etc.) and species (e.g. elephant, tiger, etc.). Each animal enclosure has a unique enclosure number, plus a type (e.g. cage, field, etc.) and size in square feet. An animal is assigned to one enclosure; an enclosure can house many animals. The Memphis Zoo also wants to keep tracks of the construction or manufacturing companies that created the enclosures. Company names are assumed to beunique. There is also a requirement to record each company'scity and state. Assume that each enclosure was created by one company. Of course, a company could be responsible for creating many enclosures.

The Memphis Zoo employs a staff of veterinarians. Each veterinarian has a unique employee number. The Zoo also wants to record their name and the set of skills that each has. Some veterinarians supervise other veterinarians. The Zoo also wants to maintain data about the university at which each veterinarian received their Doctor of Veterinary Medicine degree. University names are unique. The Zoo also wants to record the state in which the university is located, as well as the date that the university was founded. It is important to record the history of veterinarians performing medical procedures on the animals. A veterinarian can treat many animals and an animal, over time, can be treated by many veterinarians. For each such treatment, the Zoo wants to record the type of procedure and the date on which it was performed.

The Memphis Zoo also wants to maintain records about the food that the animals eat. Each animal is assumed to eat just one food item (e.g. beef, carrots, etc.) Each food item has a unique food number, plus a name and type (e.g. meat, vegetable, etc.) Food suppliers have a unique company name, plus an address and phone number. Each supplier can supply several food items and a food item can be supplied by several suppliers. For each food delivery, the Zoo wants to record the date, quantity, and unit price.