Final answer:
Europa's internal heat source, tidal heating, provides the energy for differentiation by warming its ocean of liquid water under the icy surface.
Step-by-step explanation:
Europa, one of Jupiter's moons, has an internal heat source called tidal heating that warms its large ocean of liquid water under the icy surface. Tidal heating is caused by the gravitational forces exerted by Jupiter and its other moons, which create friction and heat in Europa's interior. As a result, Europa may have hot or warm springs similar to those found in the deep oceans of Earth. This internal heat generated by tidal heating provides the energy for differentiation, the process by which Europa's ocean and surface mix and exchange materials.