During World War II (1941–45), Engel's law applied. As income rose, consumption of food dropped relative to all other goods and services purchased

The figure above shows a firm in a perfectly competitive market. If the price rises from P3 to P4 then output will increase by

A) 0 units. B) 1 unit. C) 2 units. D) 3 units.

Trade measures are usually not the best way of addressing problems such as pollution and child labor because

A) it is more efficient to address these problems at the production and consumption level. B) trade measures are not effective in reducing pollution. C) the governments of high-income countries are not interested in sanctioning pollution and child labor. D) the WTO prohibits most trade sanctions.