Answer:
The correct answer is comets.
Step-by-step explanation:
Comet is an icy, small, and rocky bodies found in space, which discharge gas or dust. They are also called dirty snowballs. It is not considered as the satellite of other objects. It does not exhibit adequate gravity to clear away smaller objects close to its orbit. When it passes close to the Sun, it sheds extra of its ice, and its surface may get surrounded with darkish dirt and would seem more like an asteroid.