2 a. Write a program to using the principle of control structures (if /else statements) determine which the students grade, based on the marks numbers entered by the user (Using the table below). From...

Extracted text: 2 a. Write a program to using the principle of control structures (if /else statements) determine which the students grade, based on the marks numbers entered by the user (Using the table below). From To Grade 90 100 A 80 89 B 70 79 C 69 F b. Write an algorithm to determine the average of any six (5) numbers and display the below after: The sum, the product and the average. - c. Describe what is a variable and how is it used in a program.