Question

what is the defining difference between eukaryotes and prokaryotes? prokaryotes are larger than eukaryotes. eukaryotes have a cell nucleus, while prokaryotes do not. prokaryotes have a cell nucleus, while eukaryotes do not. eukaryotes are larger than prokaryotes.

Explanation:

To determine the defining difference between eukaryotes and prokaryotes, we analyze each option:

• "Prokaryotes are larger than eukaryotes" is incorrect. Eukaryotes are generally larger.
• "Eukaryotes have a cell nucleus, while prokaryotes do not" is correct. The presence of a membrane - bound nucleus (and other organelles) is a key defining feature. Prokaryotes have their genetic material in a nucleoid region without a nuclear membrane.
• "Prokaryotes have a cell nucleus, while eukaryotes do not" is incorrect as it reverses the correct relationship.
• "Eukaryotes are larger than prokaryotes" is a true statement about size, but size is not the defining difference between the two. The defining difference is the presence/absence of a cell nucleus.

Answer:

B. Eukaryotes have a cell nucleus, while prokaryotes do not.