Final answer:
Younger galaxies, which are the most distant from us, were generally smaller and less massive and lacked the well-defined structures of spiral or elliptical galaxies seen today.
Step-by-step explanation:
The observable characteristics of younger galaxies, which are also the most distant from us, show that they were generally smaller and less massive compared to the galaxies we see in the universe today. In comparison to current large galaxies like the Milky Way, which are often either spiral or elliptical, these younger galaxies had not yet fully developed the features typically associated with mature galaxies. Over billions of years, galaxies can evolve significantly due to stellar formation processes and collisions with other galaxies, transitioning from irregular and less defined forms to the classic spiral and elliptical shapes seen in many older, nearby galaxies.