Context diagram and Decision table, drawing help

In the Apply Your Knowledge section found at the end of Chapter 5 in your textbook, reference Mini Case 2 and Mini Case 3. Students will submit a context diagram for the order system, and create a decision table, to be submitted as a Word document. 

Kitchen Gadgets

Kitchen Gadgets sells a line of high-quality kitchen utensils and gadgets. When customers place orders on the company's Web site or through electronic data interchange (EDI), the system checks to see if the items are in stock, issues a status message to the customer, and generates a shipping order to the warehouse,which fills the order. When the order is shipped, the customer is billed. The system also produces various reports.Tasks

1. List four elements used in DFDs, draw the symbols, and explain how they are used.

2. Draw a context diagram for the order system.

3. Draw a diagram 0 DFD for the order system.

4. Explain the importance of leveling and balancing.

Big State University

The Big State University course catalog reads as follows: "To enroll in MIS 260, which is an advanced

course, a student must complete two prerequisites: MIS 120 and MIS 222. A student who completes

either one of these prerequisites and obtains the instructor's permission, however, will be allowed to

take MIS 260."

Tasks

1. Create a decision table that describes the Big State University course catalog regarding eligibility for

MIS 260. Show all possible rules.

2. Simplify the table you just created. Describe the results.

3. Draw a simplified decision tree to represent the Big State University catalog. Describe the results.

4. Why might you use a decision tree rather than a decision table?

 Please do not copy paste any diagrams and send as answers, I am looking for good and unique explanations.