What is a key characteristic of a belief system to be classified as a religion?

A key characteristic of a belief system classified as a religion is that it must address ultimate questions. Religious belief systems often provide answers to profound queries concerning existence, purpose, morality, the nature of the universe, and the afterlife. This capacity to engage with such fundamental concerns sets religions apart from other belief systems or ideologies that may not delve as deeply into existential or metaphysical issues.

By addressing ultimate questions, religions can offer a framework for understanding life and the human condition, guiding followers in their beliefs, practices, and values. While other aspects—such as rituals, community, or social justice—may be associated with a religion, the core ability to grapple with these deeper questions is what fundamentally helps to define it as such. The other options, while they may describe features present in some religions, do not encompass the essential nature of what makes a belief system a religion.