Explain what domains are and why those are important levels of classification

The Three Domain System, developed by Carl Woese, is a system for classifying biological organisms.As scientists learn more about organisms, classification systems change. Genetic sequencing has given researchers a whole new way of analyzing relationships between organisms.
The current system, the Three Domain System, groups organisms primarily based on differences in ribosomal RNA structure. Ribosomal RNA is a molecular building block for ribosomes.

To summarize the similarities and the differences between organisms in the domains, I worked out a table for easy reference. I have attached it with this post.

 The development of eukaryotes can be known through the 'Endosymbiotic Theory of Evolution of Eukaryotic Cells'.  If you want a further explanation on this one, let me know.

Thank you ... though I am not Vanessa702.