Which of the following best describes asteroids?

Asteroids are primarily rocky objects that orbit the Sun, and they are most commonly found in a region known as the asteroid belt, which lies primarily between the orbits of Mars and Jupiter. This location is significant because it is where a large population of these celestial bodies resides, and they are remnants from the early solar system that never coalesced into planets. The composition of asteroids is predominantly rock and metal, which further supports the characterization of them as rocky objects.

The other options do not accurately reflect the nature of asteroids. For instance, while some celestial bodies exist in the outer solar system, such as Kuiper Belt objects and some comets, they do not represent the majority of asteroids. Asteroids are not frozen bodies with visible tails; that description fits comets, which develop tails when they approach the Sun due to sublimation. Finally, the idea that asteroids are small objects that burn up in Earth's atmosphere pertains more to meteoroids; while some asteroids can enter the atmosphere and become meteors, this is not a defining characteristic of asteroids themselves. Therefore, the description of asteroids as rocky objects between Mars and Jupiter captures their essential and most accurate characteristics.