The study of how firms interact in a market is a

Over the past fifty years, there has been substantial closure of the gap in real GDP per person between which of the following groups of countries?

A) the United States and Central and South America B) Africa and Western Europe C) Central and South America and Africa D) the United States and Japan

Charlie's consumer surplus from the first slice of pizza he buys is greater than the consumer surplus from the second slice because of

A) decreasing marginal benefits. B) increasing marginal benefits. C) decreasing marginal costs. D) increasing marginal cost.