Which worldwide religion is second to christianity in membership numbers?

Islam

Explanation:

Islam is the religion that is second to Christianity in membership numbers, with roughly 24.1% of the world's population following this religion. This is the religion that Muslims follow. Islam is closely related to Christianity, as both religions are Abrahamic, monotheistic religions. Islam teaches that there is only one God, called Allah, and that Muhammad is the main messenger of God. Moreover, people who believe in Islam believe in the teachings of the Quran, their religious text.

b) race riots in several cities