A measure of the responsiveness of demand to changes in income, all other things being constant, is

Which of the following appropriately applies the law of comparative advantage?

a. Countries with small amounts of labor relative to capital should specialize in producing labor-intensive commodities. b. Since Mexican labor is cheaper than American labor, trade between the countries results in exploitation of American workers. c. Since workers in countries such as the United States utilize larger amounts of capital than workers in less developed nations, trade between capital-rich and capital-poor nations results in the exploitation of labor in the less developed countries. d. Countries that are low cost producers of agricultural products should trade those products for goods they can produce only at a high opportunity cost.

A firm's supply curve is upsloping because:

A. the expansion of production necessitates the use of qualitatively inferior inputs. B. mass production economies are associated with larger levels of output. C. consumers envision a positive relationship between price and quality. D. beyond some point the production costs of additional units of output will rise.