Studying white power groups by observing their activities without participating in their activities is considered an example of

Field research.

Explanation:

When a scientist or professional does field research, the person collects information by observation and no interaction with the observed ones. The aim is to understand how a group, community, or society works in its natural environment. In this case, the professional observes the white power groups' activities to collect the necessary information that they need for the investigation.

answer; which categories of people are most at risk of becoming a criminals;

answer; all over the above; //everybody