Which of the following statements about the domains Archaea and Eukarya is correct?

• A. Both Archaea and Eukarya contain organisms with cells that have nuclei.
• B. Only Eukarya contains organisms with cells that have nuclei; Archaea lack a true nucleus.
• C. Both Archaea and Eukarya lack membrane-bound organelles.
• D. Archaea and Eukarya are both classified as prokaryotes.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the key difference between prokaryotic and eukaryotic cells. Prokaryotic cells do not have a true nucleus or membrane-bound organelles, while eukaryotic cells do.
2. Step 2: Recall that the domain Eukarya consists of organisms with eukaryotic cells, meaning their cells have a true nucleus and membrane-bound organelles.
3. Step 3: Recognize that Archaea are prokaryotes, so their cells lack a true nucleus and membrane-bound organelles, even though they share some molecular similarities with Eukarya.
4. Step 4: Evaluate each statement based on this knowledge: Archaea do not have nuclei, so any statement claiming they do is incorrect; Eukarya do have nuclei, so statements about nuclei apply only to them.
5. Step 5: Conclude that the correct statement is the one that says only Eukarya contain organisms with cells that have nuclei, while Archaea lack a true nucleus.