ribosome chloroplast membrane nucleus endoplasmic reticulum
I gave my students this multiple choice question: All cells, prokaryotic and eukaryotic, have a few common features. Which cell feature is found in both prokaryotic and eukaryotic cells?

Only one answer is correct among these 4 choices:
- ribosome
- chloroplast membrane
- nucleus
- endoplasmic reticulum

Could you tell me which one is correct?

ribosome