Answer:
spiral
Step-by-step explanation:
A galaxy may be defined as the huge collection of celestial bodies like the stars, planets, dark matters, dust and gases and the solar systems. It is derived from the Greek work, 'Galaxias' , which means "milky". There are many types of galaxies. They are : Spiral galaxy, Elliptical galaxy, Irregular galaxy and Barred spiral galaxy.
A spiral galaxy is one which contains a sphere shaped bulge which consists of old stars and it is devoid of dust and gas. Its circular shape composes a disk. It is of circular shape having most of the objects concentrated in its center.