Question

living cells can be divided into two which have nuclei, and prokaryotic cells, which do not. single - celled organisms may have eukaryotic or prokaryotic cells. however, all multicellular organisms have eukaryotic cells.
which choice completes the text so that it conforms to the conventions of standard english?
a categories: eukaryotic cells,
b categories. eukaryotic cells,
c categories, and eukaryotic cells,
d categories, eukaryotic cells:

Explanation:

The sentence is about classifying living cells into two types: eukaryotic (with nuclei) and prokaryotic (without nuclei). The correct punctuation and structure should introduce the two categories. Option B uses a colon to introduce the categories and a comma to separate the two cell types clearly, following standard English conventions for listing categories.

Answer:

B. categories: Eukaryotic cells,