Single cell eukaryotes also exist. Is it strictly true that there are no multicellular prokaryotes (what they call bacteria) or archaea? No exceptions at all?
They can form colonies and, within groups that share walls, specialize into different functions such as photosynthesis or nitrogen fixing behavior. This enables the colony to adapt to changing conditions that, while still made up of individual organisms, collectively appear to function similarly to a single multicellular one.
With that said, there aren't any examples of truly multicellular organisms within either domain. Just as an ant colony is not a single organism, cyanobacteria colony specializations are not examples of organs.
Yes, "with eukarya containing all multicellular organisms" does not mean "all eukarya are multicellular organisms" it means "multicellular organisms are a subset of eukarya".
> Is it strictly true that there are no multicellular prokaryotes (what they call bacteria) or archaea?
First off, "prokaryotes (what they call bacteria)" is incorrect. Both archaea and bacteria, in the three-domain model referenced in the article, are prokaryotes.
Second, correct, everything understood as a multicellular organism -- as distinct from colonies of unicellular organisms -- is composed of cells with nuclei, classified in eukarya in the three-domain model.
(There is a newer proposed two-domain model which disposes with Eukarya as a top-level domain, folding it under Archaea; in that model, clearly, there are multicellular Archaea.)
I suppose it depends on which model you use, and as discussed they seem to vary and be in flux right now, but the three domain model I learned was prokaryotes, archaea, and eukaryotes - the first two being different domains.
> Yes, "with eukarya containing all multicellular organisms" does not mean "all eukarya are multicellular organisms" it means "multicellular organisms are a subset of eukarya".
We agree. I don't grasp your point?
your original comment didn't refute the quote, but one needs to squint hard to see that you didn't refute it.
Not everything is an argument or attack.
> with eukarya containing all multicellular organisms
Single cell eukaryotes also exist
My point is that your statement here looks like a refutation to most, even though I know you did not intend it to be.