What is the typical composition of bright nebulae?

Bright nebulae are primarily composed of gas and dust, which play a crucial role in their formation and appearance. These regions are often sites of star formation, where the dense concentrations of gas, primarily hydrogen, and tiny particles of dust come together under gravitational forces.

The gas within bright nebulae can become ionized by the radiation from nearby young, hot stars, which causes them to shine brightly and create the glowing effect that characterizes these nebulae. Additionally, the dust present in these areas helps to absorb and scatter light, contributing to the overall visual complexity and richness of their structures.

The other options, such as solid materials, liquid forms of hydrogen, or comets and asteroids, do not accurately represent the primary constituents of bright nebulae. Solid materials or liquid states are not predominant in these vast regions of space, which are largely dominated by the gaseous state of matter in the form of ionized hydrogen and other elements, alongside dust grains that enhance their optical properties.