Which characteristic defines a meteoroid?

A meteoroid is defined as a small rocky body traveling in space. This characterization emphasizes its size and composition, typically being significantly smaller than asteroids and often made of rock or metal. Meteoroids originate from comets, asteroids, or other celestial bodies, and they traverse the solar system, which is a crucial aspect of their definition.

The characteristics of the other options do not accurately define a meteoroid. For instance, while some meteoroids may contain ice, not all are composed of ice, which eliminates the first option. Similarly, meteoroids are generally much smaller than comets; hence, they cannot be larger than a comet. Lastly, while a meteoroid becomes a meteor when it enters the Earth’s atmosphere, this transformation does not define the meteoroid itself, making that option inaccurate as well. Thus, the defining feature of a meteoroid is its identity as a small rocky body in space.