Final answer:
The religious center of the Muslim religion is Mecca, which is the birthplace of Prophet Muhammad and home to the Kaaba, the most sacred site in Islam.
Step-by-step explanation:
The religious center of the Muslim religion is Mecca. Islam is a monotheistic faith that reveres Mecca as the holiest city, as it is the birthplace of the Prophet Muhammad and the site of the Kaaba, which is the most sacred structure within the sacred mosque, Al-Haram. Every Muslim is encouraged to perform the Hajj, a pilgrimage to Mecca, at least once in their lifetime if they are able to do so. Mecca's significance in the Islamic faith is unparalleled, with millions of adherents coming together annually for Hajj, circling the Kaaba in a display of devotion and unity.