You have been hired as a Research Assistant at a hospital. As part of your training, you are to create a PowerPoint presentation on historical issues in human research and how current practices address ethics concerns. You must choose one of four articles on unethical studies: the Tuskegee Syphilis Study, Henrietta Lacks, Nazi medical experiments, or the Thalidomide trials. The presentation should define ethics, explain the background and hypothesis of the chosen study, discuss the role of institutional review boards, and identify which current ethics principles were violated and how violations are prevented now.