Exposition vs. Description vs. Casue & Effect Modes

Expostition Writing

Exposition is explanatory writing
Exposition can be an incidental part of a description or a narration, or it can be the heart of an article
Aside from clarity, the key problem with exposition is credibility. What makes your explanation believable? Normally, writers solve this problem by citing authorities who have good credentials and good reason to be experts in the subject.
http://www.longleaf.net/ggrow/modes.html

Description Writing

Creates a main impression-an overall effect, feeling, or image -about the topic
Uses concrete, specific details to support the main impression
Uses details that appeal to the five senses: sight, hearing, smell, taste, and touch

http://ksdl.ksbe.edu/writingresource/description.html

Cause & Effect

In this kind of essay, the aim is to explain the causes (reasons) or the effects (results) of an event or situation.
e.g. Causes of air pollution (multiple factors leading to air pollution).
e.g. Effects of watching too much TV (many effects of a situation).

http://www.buowl.boun.edu.tr/students/types%20of%20essays/Cause%20and%20effect%20Essay.htm

At first I was just going to go with description. However, after looking into the different modes a little moreI feel my paper would best be written with cause and effect along with exposition. I need to explain in detail the problem and connect it to the media but I also want to show the effects of the problem.