The bottom panel, for comparison, is an aerial view of San Francisco, of the same size and resolution. The pictures of Europa bear a strong resemblance to the frozen surface of the Arctic Ocean here on Earth. In the Arctic Ocean, a thin ice sheet is broken up, by ocean currents, into ice floes a few kilometers across. It is tempting to conclude, from the similarity in appearance, that the same process is occurring on Europa. In that case, the seemingly solid icy surface of Europa forms only a very thin skin atop a deep ocean of water.
Cold slush is less favorable for the formation of life than a nice warm ocean.
We don't know - there's simply not enough evidence yet.