<span> The highest ranked category or the highest taxonomic rank of organisms is a domain. Carl Woese designed three-domain system of taxonomy which includes Eukarya, Bacteria and Archea, and they differ in rRNA. The first includes all living organisms that have a nucleus and membrane-bound organelles and multicellular organisms. Other two are prokaryotic microorganisms or single-celled organisms whose cells have no nucleus. </span>
I am pretty sure its Detailed instructions correct me if I'm wrong hope this helps.
Testable, possible explanation for a scientific problem
they help us see because the retina also contains the nerves that tell the brian what the photoreceptors are seeing