Recent findings lend strong support to the theory that a black hole lies at the center of the milky way and of many of the 100 billion other galaxies estimated to exist in the universe.(a) that a black hole lies at the center of the milky way and of(b) that a black hole lies at the milky way's center and(c) that there is a black hole lying at the milky way’s center and(d) of a black hole lying at the milky way's center and(e) of a black hole that lies at the center of the milky way and of

the answer would be a

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.