Final answer:
Ethics is the normative study of moral principles and values that guide behavior, with normative ethics, metaethics, and applied ethics being its three main branches. A person is ethical when acting in accordance with established moral principles.
Step-by-step explanation:
The correct statement that defines the use of ethics is, "Ethics is the study of moral principles and values that govern individual and group behavior." This falls within the realm of normative ethics, which is a branch of ethical studies focusing on the criteria or principles that guide proper behavior. Normative ethics, along with metaethics and applied ethics, composes the three main areas of ethics.
Metaethics delves into the nature, origins, and meanings of ethical concepts, whereas applied ethics concerns itself with the application of ethical theories to real-life situations and contentious issues. For a person to be considered ethical, they must be aware of these principles that inform moral conduct and must act in ways consistent with them.
Moral philosophy is a discipline that aims to understand, justify, and explain moral principles, where morality refers to the set of rules that an individual adheres to, while ethics involves the systematized study of these moral principles.