What type of galaxy lacks spiral arms and typically has an oval shape?

An elliptical galaxy is characterized by its smooth, oval shape and the absence of spiral arms. These galaxies can vary in shape from nearly spherical to more elongated forms. They mainly contain older stars and have less interstellar gas and dust compared to spiral galaxies, which is why they typically do not form new stars. The lack of distinct arms is a definitive feature that distinguishes elliptical galaxies from spiral and lenticular galaxies.

In contrast, spiral galaxies feature prominent spiral arms composed of stars and nebulae, while irregular galaxies have no distinct shape or structure, resulting in a more chaotic appearance. Lenticular galaxies represent a transitional form between spiral and elliptical galaxies and may display a central bulge and a disk but typically lack the spiral arms seen in spirals. Therefore, the oval shape and absence of spiral arms clearly identify elliptical galaxies as the correct choice.