Question

The presence of a membrane-enclosed nucleus is a characteristic of ________.

a. prokaryotic cells

b. eukaryotic cells

c. all cells

d. viruses

Short answer

The presence of a membrane-enclosed nucleus is a characteristic of eukaryotes. Hence, the correct answer is an option (b) eukaryotic cells.

Step-by-step solution

Explanation

The cells can be of two types: prokaryotic cells and eukaryotic cells. The prokaryotic cells don't have the membrane-bound nucleus or organelles, while eukaryotes do have the membrane-bound nucleus. The word 'eu' means true and karyon means nucleus, hence eukaryotes have the true nucleus.

The viruses are acellular which means they don't contain most of the cellular characteristics like membrane-bound organelles.

Final answer

Hence, the option 'b' eukaryotic cells are correct.