The structure of a comet is considered to be like a large, or a mass of frozen ice and rock.
a. solid planet
c. cratered moon
b. dirty snowball
d. none of the above

dirty snowball

Explanation:

A comet is composed of rocks and frozen water and gasses. It is also explained as dirty snowball. Comets reside in the outskirts of solar system in Kuiper belt and Oort clouds. They orbit around the Sun. The comets visit inside the solar system when their path is perturbed by the disturbance caused in the near by star.

A comet has three parts:

1. Nucleus - It is the solid rocky core.

2. Coma- atmosphere of a comet

3. Tail - coma extends backwards when a comet comes near the Sun.

Sublimed frozen gasses and dust forms the coma and Tail.

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.