Why might scientists conclude that we are living in a spiral galaxy and not in a elliptical or irregular galaxy?

Scientists conclude that we are living in a spiral galaxy, specifically the Milky Way, due to its distinct characteristics, such as the presence of prominent spiral arms, which are regions of active star formation and dust. Observations of the galaxy's structure, including its flat disk and central bulge, align with the morphology of spiral galaxies. Additionally, the rotation curves of stars and gas in the Milky Way indicate a disk-like structure typical of spiral galaxies, distinguishing it from elliptical and irregular types. These features collectively support the classification of the Milky Way as a spiral galaxy.