List and discuss three reasons Islam spread so rapidly in Africa

Please provide the best answer for the statement.

1. Scholars once believed that the rapid expansion of Islam was entirely due to the determination of the faithful to convert new followers to the faith.
2. However, overpopulation of the Arabian peninsula probably also played a role. If faith offered the excuse, the practical result of Islamic expansion was the acquisition of new territories and the wealth they brought with them.
3, After gaining control of virtually all of the Middle East, the Arabic Muslim armies moved into North Africa in 639. After gaining control of the port of Alexandria, they launched a navy that seized Cyprus and Rhodes and began attacking Italy and Sicily. They moved across North Africa and took Carthage in 698, defeating the native Berber tribes. Beginning in about 750, not long after Muslim armies had conquered most of North Africa, Muslim traders, following the trade routes created by the Saharan Berber peoples, began trading for salt, copper, dates, and especially gold with the sub-Saharan peoples of the Niger River drainage. Gradually they came to dominate the trans-Saharan trade routes, and Islam became the dominant faith of West Africa.
4. Local people took advantage of increased opportunities for wealth and power brought by Muslim influence, participating in expanded trade (including the slave trade) and forming powerful states.
5. Muhammad accepted slavery as the just spoils of war, although no Muslim was ever to enslave another Muslim. There is some reason to believe that many African converts to Islam were initially attracted to the religion as a way to avoid becoming slaves, since the faithful were exempt from servitude.