Final answer:
Thermohaline currents driven by temperature and salinity differences are the fastest and deepest ocean currents.
Step-by-step explanation:
The fastest and deepest ocean currents are Thermohaline currents driven by temperature and salinity differences. These currents are also known as the global conveyor belt and are responsible for the circulation of deep ocean waters. They are driven by differences in temperature and salinity, which create variations in water density.