Communism and socialism are usually found in what type of economic system?

It is found in the command type of an economic system ; )

Explanation:

D) Constantinople was a Christian city from which the Crusaders marched on Jerusalem.

Explanation:

Constantinople was strategically located in the Bosphorus, between the Golden Horn and the Marmara Sea. Because of this location, this city was a connection between Europe and Asia. However, during the crusades, this city was a post, almost as if was a shelter, for the pilgrims and soldiers who were going to Jerusalem to pray or to fight. There, they would find a place to rest, and at the same time, it was the door for the East.