Which kind of galaxy has a flat, rotating disk with stars, gas, and dust?

A spiral galaxy is characterized by its flat, rotating disk structure, which contains stars, gas, and dust, along with a central concentration of stars known as the bulge. The arms of a spiral galaxy extend outward from the center and are regions where star formation is actively occurring, making them visually striking and often brighter than other parts of the galaxy.

The presence of both a disk and a central bulge distinguishes spiral galaxies from other types. While barred galaxies also have a similar structure, they possess a bar-shaped feature in their central region. In contrast, irregular galaxies lack a defined shape and elliptical galaxies are more three-dimensional, typically lacking the flat disk structure that is emblematic of spiral galaxies. This specific configuration of a spiral galaxy facilitates the ongoing processes of star formation, which is fundamental to its characteristics and evolutionary dynamics.