Answer: cluster
Step-by-step explanation:
There are four main shapes of galaxies: spiral, galaxies are divided into four main groups: spiral, lenticular, elliptical, and irregular, elliptical, and irregular.
The least common shape is cluster
Spiral galaxies- These are the most common. These have arms extending from a bright bulge in spiral shape.
Elliptical galaxy have ellipsoidal shape.
Lenticular galaxies - Intermediate between elliptical and spiral galaxies.
Irregular shape- No well defined shape
Spherical - Nearly spherical galaxies. These are least
cluster- group of galaxies having irregular shape is the least common shape.