Which phrases describe a irregular galaxy

An irregular galaxy is the one which does not have any shape. It means it does not fit into the categories described by the Hubble. Such types of galaxies contain large amount of dust and gases. These are a site of stellar formation and hence contain young stars and are very bright. these galaxies are usually smaller than other types of galaxies. for example: Large Magellanic Clouds and Small Magellanic Cloud.

"the periodic table is arranged in order of atomic number."