What I want to know about my topic

I have multiple questions for my research project. There are so many questions I could ask about nursing. There are so many different things I could learn about.  I will have many more questions as i research this topic. My essential question is "What is the difference between a CNA, RNA, and a LPN?" This is a broad question that can have many other questions to help me figure out its answer.

• What are the college requirements for each level?
• What is the salary for each level?
• Which level has more job openings? And why?