Customs that govern the behaviour of an individual or a group of people is a definition of:Group of answer choicesMoralityEthicsPhilosophyHumanity

The definition provided refers to the norms and practices that guide the behavior of individuals or groups. Here's a breakdown of the provided options:

1. Morality: This term typically refers to the principles concerning the distinction between right and wrong or good and bad behavior. While it can govern behavior, it is often more about personal beliefs.

2. Ethics: Ethics is a branch of philosophy that involves systematizing, defending, and recommending concepts of right and wrong behavior. This term is more closely associated with the customs guiding collective behavior within groups or societies.

3. Philosophy: This is the study of fundamental questions regarding existence, knowledge, values, reason, mind, and language. It does not specifically refer to customs governing behavior.

4. Humanity: This term generally refers to human beings collectively, or the quality of being humane and kind. It isn’t specifically about behavior customs.

Based on this analysis, the best answer to the question is Ethics, as it specifically involves the customs that govern the behavior of individuals or groups.