It was primarily the development of agriculture that led to the development of the first city states, since this allowed for there to be a surplus of food, which allowed people to have labor specialization.
The correct answers are:
- common trade regulations;
- free movement of capital and labor;
- free movement of goods;
The economic unions are made with the purpose of enabling two or more countries to be able to trade between each other with ease and without restrictions and problems. The labor force to be able to move freely in each of them, if there's need for it of course, as well as the free movement of capital, and free movement of goods. These things are all made in a way that they will be well suited for each member of the economic union, and that it will enable the economy of each member to improve.
