In the above figure, a surplus exists in the gasoline market when the price is

Comparisons between industrialized nations and less-developed countries indicates that as income rises, the demand for a clean and well-preserved environment

a. increases by a proportional amount. b. decreases by a proportional amount. c. increases by a more than proportional amount. d. decreases by a less than proportional amount.

Consider two individuals — Howard and Mai — each of whom would like to wear sweaters and eat tasty food. The gains from trade between Howard and Mai are least obvious in which of the following cases?

a. Howard is very good at knitting sweaters and at cooking tasty food, but Mai's skills in both of these activities are very poor. b. Howard is very good at knitting sweaters and at cooking tasty food; Mai is very good at knitting sweaters, but she knows nothing about cooking tasty food. c. Howard's skills in knitting sweaters are fairly good, but his skills in cooking tasty food are fairly bad; Mai's skills in knitting sweaters are fairly bad, but her skills in cooking tasty food are fairly good. d. Howard's skills are such that he can produce only sweaters, and Mai's skills are such that she can produce only tasty food.