In a monetary system, people will exchange a good for

The gravity equation was tested and found to be very accurate in predicting:

a. world trade in total. b. trade between various provinces in Canada and American states. c. trade between the United States and Japan. d. trade between nations in the European Union.

In which of the following cases is the slope of a line positive?

A) As x increases, y increases. B) As x increases, y decreases. C) As x increases, y remains the same. D) As x increases, y equals a positive number.