Final answer:
The fundamental reason for the existence of the church is to be a corporate body in which believers can worship God together.
Step-by-step explanation:
d) To be a corporate body in which believers can worship God together
One of the fundamental reasons for the existence of the church is to provide a corporate body in which believers can worship God together. This means that the church serves as a place for believers to come together, express their faith, and engage in communal worship. This aspect of the church is important because it allows believers to strengthen their spiritual connection and grow in their faith.