Short answers, pulled from the story.
Islam is an Abrahamic monotheistic religion based on the Quran and the teachings of Muhammad. Its central belief is tawhid, the oneness of God, along with belief in angels, revelation, prophets, the Day of Resurrection, and divine predestination. Muslims hold the Quran to be the verbatim, final, and unaltered word of God.
As of 2020, about 2 billion people, or roughly 25.6 percent of the world's population, are Muslims, making them the second-largest religious population after Christians. About 65 percent live in ten countries, with the largest populations in Indonesia, Pakistan, India, Bangladesh, and Nigeria.
The Five Pillars are the shahada (declaration of faith), salah (five daily prayers), zakat (almsgiving of 2.5 percent of accumulated wealth), sawm (fasting during Ramadan), and hajj (pilgrimage to Mecca). They are considered obligatory acts of worship for Muslims.
Islam originated in Mecca around 610 CE, when Muslims believe Muhammad received his first revelation in the Cave of Hira on the mountain Jabal al-Nour. By the time of Muhammad's death in 632, most of the Arabian Peninsula had converted to Islam.
Sunni Islam makes up about 87 to 90 percent of Muslims and holds that the first four caliphs were Muhammad's rightful successors. Shia Islam, about 10 to 13 percent, holds that leadership belongs to Muhammad's family through his cousin Ali, the ahl al-bayt. The divide initially arose from disagreements over succession to Muhammad and later grew theological and juridical.
Muslims are the fastest-growing major religious group primarily because of a higher fertility rate and a younger age structure compared to other major religions. Conversion has little net effect, since the number entering and leaving the faith is roughly equal. Projections suggest the Muslim share of the global population will reach 29.7 percent by 2050.