Which of the following is not an assumption generally made in the study of international economics?

a. two nations

b. two commodities

c. perfect international mobility of factors

d. two factors of production

.Which of the following is not a reason for increasing opportunity costs?

a. technology differs among nations

b. factors of production are not homogeneous

c. factors of production are not used in the same fixed proportion in the production of all commodities

d. for the nation to produce more of a commodity, it must use resources that are less and less suited in the production of the commodity

9.If the autarky Px/Py is lower in nation 1 than in nation 2 without trade:

a.nation 1 has a comparative advantage in commodity Y

b.nation 2 has a comparative advantage in commodity X

c. nation 2 has a comparative advantage in commodity Y

d.none of the above

10.Mutually beneficial trade cannot occur if production frontiers are:

a. equal but tastes are not

b. different but tastes are the same

c. different and tastes are also different

d.the same and tastes are also the same.

11.Trade allows nations to attain and indifference curve that is

a. beyond the indifference curve it could attain without trade

b. inside the indifference curve it could attain without trade

c. is positively sloped

d. is negatively sloped

12.At a relative commodity price above equilibrium

a. the excess demand for a commodity exceeds the excess supply of the commodity

b. the quantity demanded of imports exceeds the quantity supplied of exports

c. the world price of the commodity will fall

d. the excess demand for the commodity will increase.

please also provide the reason for answers