Final answer:
The nurse is acting as an advocate, ensuring the patient is thoroughly informed about the risks of a research study for proper consent.
Step-by-step explanation:
The nurse in the scenario is playing the role of an advocate for the patient. This advocacy is crucial when patients are invited to participate in research studies, as it involves ensuring that they are fully informed of all risks and benefits and can give informed consent. The nurse's actions highlight the importance of transparency and patient autonomy in healthcare, reinforcing the ethical standard that all study participants must have a clear understanding of the research they are being asked to participate in.