Stratified Randomization ensure that

A. to examine whether the proposed research is properly designed: Ensuring that research is properly designed is primarily the responsibility of the Institutional Review Board (IRB) or ethics committee. While investigators design the study, the formal evaluation of methodological soundness and ethical compliance is conducted by an independent review body.

B. to determine whether or not to participate in the research: Determining participation is the responsibility of the potential research subject, based on the principle of respect for persons. Through informed consent, individuals decide whether the potential risks and benefits are acceptable to them. This decision-making authority belongs to participants, not investigators.

C. to determine whether the risks that will be presented to subjects are justified: Under the principle of beneficence in the Belmont Report, investigators are responsible for conducting a thorough risk–benefit assessment. They must minimize potential harms and ensure that anticipated benefits justify any risks involved. This includes designing procedures that reduce exposure to unnecessary physical, psychological, or social harm.

D. All of the above: Although multiple parties share ethical responsibilities in research oversight, the investigator’s specific duty under beneficence focuses on assessing and justifying risks relative to benefits. Therefore, not all listed options fall under the investigator’s direct responsibility.

The scientific approach involves using structured, evidence-based methods to explore phenomena, gather data through observation or experimentation, and analyze results critically. It emphasizes logical reasoning, reproducibility, and objectivity to test hypotheses, validate findings, and refine or develop theories. Researchers follow a systematic sequence of steps including defining a problem, reviewing literature, designing studies, collecting and analyzing data, and drawing conclusions to ensure reliability and minimize bias. This method allows scientists to build cumulative knowledge, challenge assumptions, and make informed predictions about the natural world.