What did the social class contribute to early civilization?

Well, your answer is going to be that the largest social class that there had been being farmers and also the peasants. They contributed to the society by growing crops and making food for everyone and doing a lot of the dirty work. They would support the entire city. This still applies today only now they aren't the lowest social class and often farmers can be very rich if their business is going well.

They would be more crops at 1a and 1b more than 1c