Question

A new object, Object Z, was discovered outside our solar system. Object Z is made of frozen gases that surround a rocky core and it travels in a highly elliptical orbit around the sun. The characteristics of Object Z most closely resemble those of other
A. asteroids.
B. dwarf planets.
C. comets.
D. moons.

Answer 1

That's the familiar description of a comet.

If I were the amateur astronomer who discovered the new comet, then
according to the tradition of the astronomical community, I would have
the privilege of naming it.  I would call it  Comet AL2006/2016. 

Answer 2

Answer:  C. comets.

Explanation:

• Asteroids are rocky objects majority of which are found in belt between orbits of Mars and Jupiter. Example: Ceres
• Dwarf planets are similar in composition to planets and are found in Kuiper belt. Pluto is a dwarf planet.
• A comet has a solid rocky core surrounded by atmosphere of frozen gases. Comets are present in the outskirts of the solar system and orbit the Sun in an elliptical orbit.
• Moons are are natural satellites revolving about planets. Example: Titan, Phobos and Deimos etc.

Object Z is made of frozen gases that surround a rocky core and it travels in a highly elliptical orbit around the sun.  The characteristics are similar to ones of comets. Thus, object Z closely resembles a comet.