Which of the following might have been the most beneficial factor for the spread of islam

The answer is Islam as a tradition was compatible with a trading culture. Because Islam initiated and has advanced in an Arab culture, other cultures which have accepted Islam have inclined to be influenced by Arab customs. Thus Arab Muslim societies and other Muslims have cultural affinities, though every society has preserved its unique characteristics. Arabs traditionally had a tradition of trade and commerce, the Muslims continued that tradition. It was due to their advantage in navigation, shipbuilding, astronomy, and scientific measuring devices that Arab and Muslim commerce and trade developed and reached so many peoples throughout the world.  Islamic craftsmanship in bookmaking and bookbinding were items of trade which carried the message of Islamic civilization far and widespread.

the answer is A. Islam as a tradition was compatible with a trading culture  

How did the government and the economy under Lenin differ from "pure" communism? In the government Lenin set up, the Communist Party, not the people, controlled the government. The economy under the NEP allowed some capitalist ventures.

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