(a) Discuss why a duopoly oligopoly will tend to collude rather than to compete when both parties are of equal size and produce similar product.

(b) The scientific method is being used by economists to formulate theories, laws, and principles.Explain the mechanism behind such research method in deriving economic theories.

(c) Explain the assumptions and shape of the production possibilities curve that helps to illustrate and clarify society's economizing problem.