E0 ellipticals are nearly circular, while E7s are very stretched out. Elliptical galaxies are made up of mostly old stars, and do not have much gas and dust. There is very little new star formation in these galaxies.
Mostly made of old stars
A planetary nebula is a (ring-shaped) type of nebula formed by an expanding shell of gas around an aging star. *a planetary nebula is a type of nebula*. im not completely certain though. i might be wrong.