How are a black hole and a neutron star similar and different?

Both black holes and neutron stars are corpses of stars that died in catastrophic explosions known as supernovas, outbursts that can make a star briefly outshine all of the other stars in its galaxy. When a star goes supernova, the core of its remains collapses under the strength of its own gravitational pull.

Your answer is water because there is combined mass of water found on, under, and over the surface of a planet. your answer is water.