One hypothesis to explain the changing gap in wages between unskilled and skilled workers in the United States is that international trade has altered the relative demands for skilled and unskilled workers

Assuming constant returns to scale, the equation, Y = A(t)F(K,N) can be rewritten as

a. Y/N = A(t)ƒ(K/N). b. q = A(t)ƒ(k). c. Y/N = A(t)ƒ(K ? N). d. Both a and b e. Both b and c

The key explanation for the prevalence of waterway pollution is

a. the inclusion in production of all costs involving use of the waterway. b. that there are private costs but no costs to society. c. that waterways are not private property and can be used free of charge. d. that waterways are subject to the market's normal control procedures.