Answer:
<em>The invisible hand concept</em>
Explanation:
The invisible hand concept is a metaphor which describes the actions of a person who performs certain tasks for his own benefit but his actions also lead to being a help for the public or a society.
In the scenario, mentioned in the question, Sergio wanted to earn a nice amount of profit for himself by setting up a consulting business. In his effort to do this, he benefited the society by helping them with their computer problems. Hence, this is an example of invisible hand concept.
Answer:
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<span>The crusades were a series of holy wars called by popes with the promise of indulgences for those who fought in them and directed against external and internal enemies of Christendom for the recovery of Christian property or in defense of the Church or Christian people.
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