Final answer:
Before Muhammad's revelations, the religious groups in Mecca were Pagans, Jews, and Christians.
Step-by-step explanation:
The three religious groups that one could find in Mecca before Muhammad's revelations were Pagans, Jews, and Christians. Mecca was a center of worship for a variety of deities, with the greatest being Allah (meaning "the god"). These groups practiced polytheism, Judaism, and Christianity respectively.