For a movie stunt, an empty truck with a mass of 2000 kg goes 10 m/s and runs into a stopped car of mass 1000 kg. The truck then keeps moving and pushes the car along with it. If there are no other forces acting on this system, which best describes the results of the collision? The collision is perfectly elastic. Kinetic energy stays the same. The momentum after the collision is greater than the momentum before the collision. The speed of the combined vehicles is less than the initial speed of the truck.

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.

i really dont know but i will try okay.

so i think u would just add all them up and get your answer..