Which statement about the dark nebulae is true?

Question

Quizplus · Accepted Answer

Dark nebulae are made up of small particles of dust and gas that absorb and scatter light. This makes them appear dark and opaque to visible light. However, they can be seen in longer wavelengths such as radio and infrared, which can penetrate through the dust and gas. Dark nebulae are clouds of gas and dust that block the visible light from stars behind them, but can be penetrated by longer wavelengths such as radio and infrared. Hydrogen and helium are important components of these clouds, but are not the only absorbing and scattering agents. They do not comprise the majority of the mass of the Galaxy, and do not block the vast majority of radio waves. They cannot be penetrated by shorter wavelengths such as UV and X-ray.

Which Statement About the Dark Nebulae Is True