What is the difference between a cross-sectional study and a longitudinal study? What advantages and disadvantages does each method have?

Locate a longitudinal study via the Ivy Tech online library (home) and describe in a short essay (minimum 200 words)20 points:

What is the difference between a cross-sectional study and a longitudinal study? What advantages and disadvantages does each method have?
What was the topic/hypothesis of the study you chose? In other words, what were the researchers trying to find out?
How long did the study last?
What were the findings?
Could the researchers have studied this question using another research method? Why or why not?