Please respond to the following questions, in 1-2 paragraphs per question. If you use a resource, please cite and reference the resource.

In the context of clinical research,

1. What is the purpose of the institutional review board?
2. What are essential documents?
3. What are investigator-initiated studies?
4. What is the relevance of Title 21 in the Code of Federal Regulations?
5. What is the difference between a case report form and source documentation?