What is the purpose of a domain?

A principle of material science which expect that bunches of particles delivered by development of electrons adjust themselves in bunches (called "spaces") in attractive materials. The heading of attractive field at a point is the heading to which a free north shaft would move in the event that set at that point within the field.

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.