Obtaining participants' consent in a scientific study is related to which principle?

Correct answer: Research ethics

The direct answer is A: research ethics. In a study involving people, asking for informed consent means explaining the study sufficiently and allowing participants to choose freely whether to take part. This protects their autonomy, dignity, privacy, and safety. Step by step: identify that human participants are involved; explain the purpose, procedures, possible benefits, and risks in understandable language; allow questions; make sure participation is voluntary; obtain consent before collecting data; protect personal information and allow withdrawal where appropriate. Option A is correct because consent is a basic requirement of ethical research involving human beings. Option B, “measurement precision,” concerns how closely repeated measurements agree; it does not concern permission or participant rights. Option C, “sample size,” means the number of participants or observations; a large sample still requires consent. Option D, “scientific law,” is a well-supported general relationship in nature, not a rule about treating participants. Consent is especially important because researchers have responsibility toward people who provide information or undergo procedures. Memory cue: people are participants, not merely data; ask permission and protect their rights.