Answer: Informed consent
Explanation:
Informed consent is defined as the method through which permission taken by research or experiment participant before conducting the experiment so that they can be aware about purpose,risk and possible consequences involved in the research .This way participant have knowledge about experiment on which they are being subjected.
According to the question,Margarita did not follow informed consent step before conduction of research rather she told them about the actual purpose before the students were leaving after finishing the lab experiment.