Mary is researching the factors related to alcohol use among college students, so she goes to live in a college dorm for a month to observe students and conduct in-depth interviews. this is an example of what type of research?

the historians cited in the article all agree with one another about the cause of the civil war. despite coming from different backgrounds and cultures, the historians agree that slavery was the root cause of the civil war. the fact that all these historiansgenerally agree with one another makes their shared viewpoints more reliable and valid, especially because the historians have different backgrounds and all work for the well-respected institutions of howard university, clemson university, and the university of colorado.