Here is the categorization of the galaxies based on your descriptions:
- These galaxies have unusual shapes. irregular
- In this galaxy, the arms have many young stars and the central region has older stars. spiral
- 80% of the galaxies in the universe. elliptical
- The Milky Way galaxy. spiral
- Andromeda galaxy, our closest neighbor. spiral
- Shaped like spheres or cucumbers and contain old stars. elliptical
So, the filled input would be:
- irregular
- spiral
- elliptical
- spiral
- spiral
- elliptical