Which of the following structures is present in both prokaryotic and eukaryotic cells?
A. Endoplasmic reticulum
B. Cell membrane
C. Chloroplast
D. Golgi apparatus
The structure that is present in both prokaryotic and eukaryotic cells is the cell membrane ². The cell membrane is a thin layer that surrounds the cell and separates its internal environment from the external environment ². It is composed of a lipid bilayer and proteins and regulates the movement of substances into and out of the cell ².
The other options are not correct because they are not present in both prokaryotic and eukaryotic cells. The endoplasmic reticulum, chloroplast, and Golgi apparatus are organelles that are only found in eukaryotic cells ².
Therefore, the Correct Answer is B.