Which characteristic is NOT a major component of asteroids?

Asteroids are primarily composed of solid materials, making their characteristic components include metallic minerals, rock fragments, and dust particles. Metallic minerals typically include various metals such as iron and nickel, while rock fragments make up the bulk of asteroid mass, often consisting of silicate materials. Dust particles also contribute to the makeup of asteroids, being small debris from larger bodies.

The presence of gases, however, is not a major characteristic of asteroids. Unlike comets, which are known for their icy cores and gas-producing tails due to sublime materials, asteroids lack significant gaseous compositions. Their formation processes and locations in the solar system—primarily in the asteroid belt between Mars and Jupiter—result in solid structures rather than gas-rich environments. Therefore, the absence of gases as a key component highlights a distinguishing feature of asteroids compared to other celestial bodies.