M31 is the Andromeda one.
Starburst types of these systems have unusually high supplies of gas, and they can combine in a process known as cannibalism. The "tuning fork diagram" is a graphic depiction of the Hubble classification scheme for these systems, which divides them into irregular, elliptical and spiral types. M31 is the Andromeda one. For 10 points, name these regions of the universe that include the Milky Way.
Starburst types of these systems have unusually high supplies of gas, and they can combine in a process known as cannibalism.
galaxies [or galaxy]