Final answer:
Groups such as the Ghaznavids, Arabs, and Muslim missionaries contributed to the spread of Islam into various regions through conquest and trade. Trade routes played a crucial role in this expansion, as did the principles of spatial diffusion.
Step-by-step explanation:
The question pertains to the historical expansion of Islam and the groups that played key roles in its spread. We can match the following:
- Ghaznavids: This group (a) spread Islam to Iran and Afghanistan.
- Muslim missionaries traveled along trade routes to spread Islam, hence can be associated with (c).
- Finally, Arabs (b) were instrumental in spreading Islam into Hindu-dominated India through both conquest and trade.
The role of trade routes in the spread of Islam was pivotal. These routes allowed Muslims to interact with different cultures and regions, wherein missionaries and merchants played a significant role in spreading Islamic doctrines and establishing trade relationships. Over time, the interconnectedness facilitated by these routes led to a more unified Islamic world.
Spatial diffusion also contributed to the spread of Islam especially from the trade center of Mecca. Trade and conquests expanded the Ummah, and later, the rise of empires like the Ottoman Empire and Safavids continued this expansion.
Technological advancements and scientific discoveries, often shared along these trade routes, also helped in the spread of Islamic civilization by improving travel and the efficiency of commerce. This in turn increased the influence of Islamic empires and facilitated the spread of the religion.