Which of the following is a key property of dark matter?

Dark matter is a crucial component of the universe, and one of its defining characteristics is that it interacts weakly with other forms of matter. This weakness in interaction is why dark matter cannot be detected directly through conventional means such as telescopes, which rely on the emission or reflection of electromagnetic radiation—something dark matter does not do. As a result, dark matter does not emit or absorb light or other forms of radiation, making options involving radiant emissions incorrect.

Additionally, dark matter does not constitute stars or any visible celestial bodies, which are primarily made up of normal matter composed of protons, neutrons, and electrons. Thus, while stars are visible due to their own radiation, dark matter remains undetectable through these means.

In summary, the weak interaction of dark matter with other matter is what leads scientists to infer its existence through its gravitational effects, such as on the motion of galaxies and the behavior of galaxy clusters, rather than through direct observation.