A typical cell has a layer of negative charge on the inner surface of the cell wall and a layer of positive charg on the wall outside surface, thus making the cell wall a capacitor.

What is the capacitance of a 50 um diameter cell with a 7.o nm thick cell wall whose dielectric constant is 9.0?

Because the cell's diameter is much larger than the wall thickness, it is reasonable to ignore the curvature of the cell and think of it as a parallel-plate capacitor.

f is prop to m1xm2 double m1 double force

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.