The social contract principle was introduced during the Enlightment era due to the contribution of both Jean-Jacques Rousseau and John Locke's work and ideas.
The principle describes how the power of a state resides on its citizens, who can grant it to political representatives that are elected through suffrage. Hence, citizens give up their share of state power (their individual rights). In turn, the elected representatives would propose and implement policies on their behalf. This principle is the base of modern representative democracies.
Most operas begin with an overture, an orchestral introduction that includes many of the musical themes of the piece.
There aren't any statements shown but I think i can help with the second part, artists in different times and places are influenced by the different things around them and by what is happening during that time.
For an example of different places; an artist at a beach would be more likely to draw the beach than an artist in a forest and the same way reversed.
An example of different times; an artist in the 1700s would portray people wearing different clothes than an artist would portray today.
