Final answer:
Religious observance refers to engaging with a formal religious group's doctrines, values, traditions, and co-members.
Step-by-step explanation:
Engaging with a formal religious group's doctrines, values, traditions, and co-members is known as religious observance. Religious observance involves participating in the rituals, practices, and beliefs of a specific religious group. Examples of religious observance include attending worship services, following religious laws and customs, and being involved in religious community activities.