why can't plants and animals use the nitrogen directly from the atmosphere?

a: there is not enough of it in the air.

b: nitrogen gas contains the element in an inert, unusable state.

c: they do use it directly from the atmosphere.

d: plants and animals do not need nitrogen for their life processes.

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.