Question

Ocean currents are produced by

A.
differences in the temperature of the water at different depths.

B.
volcanoes on the bottom of the ocean floor.

C.
differences in the number of organisms living at different depths.

D.
earthquakes on the bottom of the ocean floor.

Answer 1

A. Differences in the temperature of the water at different depths.

Explanation: Temperature (and salinity) differences change water density, which drives vertical and horizontal movement (thermohaline circulation). Surface currents are also driven mainly by wind and the Coriolis effect.