Why are drugs classified in the categories they are?

Homework is to be presented as a short (50-100-word) paragraph response for each question. The assignment is to be submitted as a Microsoft Word document electronically to the instructor. 1. Why are drugs classified in the categories they are? 2. Give a description of the actions of drugs in each category. 3. What is chemotherapy and which diseases are treated this way? 4. Give examples of how contrast media are used to produce an image. 5. Compare ionic and non-ionic contrast media.