Question

which of the following is an example of thermal expansion? ice floats on liquid water because it is less dense than liquid water. warm water ocean currents are found on the surface. dropping a marble in a cylinder of liquid raises the volume. when seawater freezes, salt is left behind.

Explanation:

Thermal expansion is related to change in volume due to temperature change. Warm - water ocean currents being on the surface is due to warm water expanding (less dense) and rising which is an example of thermal expansion. Ice floating is due to hydrogen - bonding and density differences not thermal expansion. Dropping a marble in liquid is displacement, not thermal expansion. Salt being left behind when seawater freezes is a separation process not related to thermal expansion.

Answer:

Warm water ocean currents are found on the surface.