If the torque on an object adds up to zero: a) the object could be accelerating linearly but it could not be turning. b) the object is at rest. c) the object cannot be turning. d) the object could be both turning and accelerating linearly. e) the forces on it also add up to zero.

D

Explanation :

Torque adds up to zero therefore the object could both be turning and accelerating linearly.

Torque is zero means that angular acceleration is zero i.e. object is rotating with constant angular velocity.

Even if force is zero, object can move i.e. with a constant velocity.

Thus Zero torque does not implies that object is not rotating.

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.