Question

which is one characteristic of deep ocean currents?
deep ocean currents move quickly.
deep ocean currents are caused by winds.
deep ocean currents move cold water toward the equator.
deep ocean currents are affected by temperature but not by salinity

Explanation:

Deep - ocean currents are slow - moving (so "Deep ocean currents move quickly" is wrong). Surface currents are mainly caused by winds, while deep - ocean currents are driven by density differences (so "Deep ocean currents are caused by winds" is wrong). Deep - ocean currents are affected by both temperature and salinity (thermohaline circulation, so "Deep ocean currents are affected by temperature but not by salinity" is wrong). Cold water is denser. Deep - ocean currents move cold, dense water from the poles (high latitudes) toward the equator.

Answer:

Deep ocean currents move cold water toward the equator.