Why can we generally describe survey research, archival research, and observational research as correlational in nature?

What will be an ideal response?

Survey, archival, and observational research rely on data obtained without manipulation of any variables. In fact, for archival and observational research, the people or animals that provide the data may not even be aware that they are being observed and measured. Because there is no manipulation of variables, we don't know why different people or animals act differently; we can only spot patterns of behaviors, which is the hallmark of correlational research.