What are critical elements of descriptive essays?

I’ve given a lot of thought to what one of them should be, and the answer seems clear.

Which situation best describes the concept of causation?

Examine an advertising campaign created by the center for disease control that promotes the influenza (flu) vaccination. analyze the campaign to discover the target audience and the advertising techniques used. then, evaluate the effectiveness of these advertising techniques. write a five-paragraph essay in which you explain how the advertising campaign effectively promotes the influenza vaccination to a range of audiences.