Surface currents are driven by
a)wind
b)density
c)salinity
d0temperature

Surface currents are MAINLY driven by wind, but sometimes they can be driven by other things such as the movement of animals and such.

You not be doing this in a quiz. if you actually studied your work you would know the answer. the answer though is that they would use gdp per capita because it measures a smaller portion (person). this could show individual growth per person in the country.