How do observations of distant galaxies us learn about galaxy evolution? a. observations at different distances show galaxies of different ages and therefore different stages of evolution. b. we can observe the birth of galaxies. c. we can observe the evolution of a single galaxy over time. d. we can observe two galaxies merging and what the result is, us learn how mergers affect evolution. e. we can see what our galaxy used to look like and therefore theorize about the physical processes that led to its current appearance?

The correct answer is a. observations at different distances show galaxies of different ages and therefor different stages of evolution.
By observing the galaxies at different distances we get their age too. In this way the scientists are able to see galaxies from all ages and stadiums of evolution, from galaxies being created, to young, middle aged and old galaxies. They can compare all of them, see how the processes work in different stadiums, can see what will happen in the future, how they die, how are they created and the beginning phases...

Don’t use up to much of them it leads to pollution