Human subjects are defined as living individuals from whom an investigator obtains data through which means?

The definition of human subjects in the context of research is centered on the interaction or intervention that occurs between the investigator and the individuals involved. This means that human subjects are considered to be living individuals from whom data is gathered through any form of interaction—such as interviews, surveys, or clinical trials—or through a specific intervention designed to affect the subjects.

When data is collected directly from individuals through interaction or intervention, it emphasizes the personal involvement of the participants, which is a key aspect of ethical considerations in research. This includes obtaining informed consent and ensuring the participants' rights and welfare are protected, as they are directly affected by the research being conducted.

While direct observation, identification through records, and survey completion can also involve human subjects, these methods do not fully encapsulate the broader definition which primarily pertains to the active engagement of living individuals in the research process. Therefore, interaction or intervention stands out as the most comprehensive answer describing how data is obtained from human subjects.