Final answer:
Elliptical galaxies are indeed classified by how round or flat they appear, being categorized from nearly spherical to very elongated shapes. Classification is based on observed elongation, using an 'E' followed by a number to denote the degree of flattiness. Giant ellipticals can be more massive than any spiral galaxy, while dwarf ellipticals tend to be quite common with smaller masses.
Step-by-step explanation:
It is true that elliptical galaxies are classified by how round or flat they appear. Elliptical galaxies can range in shape from nearly spherical to highly elongated forms that approach the flatness of spiral galaxies. They are often populated by older, reddish stars and possess no distinct spiral arms. Sizes of elliptical galaxies can vary greatly, from giant ellipticals that are more massive than any spiral galaxy, to dwarf ellipticals which are quite common and have relatively small masses.
The classification of elliptical galaxies is based on their observed elongation, which is often expressed in the form of an 'E' followed by a number representing their degree of flattening. For instance, an E0 galaxy would appear more spherical, while an E7 galaxy would appear more elongated or flat. The classification system originally developed by Edwin Hubble places elliptical galaxies on one end of the Hubble sequence, to the left of the diagram which separates them from spirals and irregulars.