Whose services cost more, a dentist or a store clerk? Why?

the anwser is missions

industrial revolution, in modern history, the process of change from an agrarian and handicraft economy to one dominated by industry and machine manufacturing

i believe it would influence their own way of understanding things. it shall be a foundation where they can draw or start an argument.   historians are also  scientists that  have their tools of analysis and expertise to unlock a variety of difficulties such as relationships of man, origin, politics, economy, and culture. based on facts and understanding on these areas, they may shade light to extract ideas and develop options to validate a hypothesis or debunk it.