Question

which statement is true of eukaryotes but not of prokaryotes?
○ they must be multicellular
○ they do not have membrane-bound organelles
○ they are always single-celled
○ they must contain a nucleus

Explanation:

1. Analyze "They must be multicellular": Eukaryotes can be unicellular (e.g., yeast) or multicellular, so this is false.
2. Analyze "They do not have membrane - bound organelles": Eukaryotes have membrane - bound organelles (e.g., nucleus, mitochondria), while prokaryotes don't. So this is false.
3. Analyze "They are always single - celled": Eukaryotes can be multicellular (e.g., plants, animals), so this is false.
4. Analyze "They must contain a nucleus": By definition, eukaryotic cells have a true nucleus (a membrane - bound nucleus), while prokaryotic cells have a nucleoid (no membrane - bound nucleus). So this statement is true for eukaryotes and not for prokaryotes.

Answer:

They must contain a nucleus.