Which two structures are common to both prokaryotic and eukaryotic cells?

Both prokaryotic and eukaryotic cells share fundamental features that are critical for their structure and function. The plasma membrane, also known as the cell membrane, is a crucial component that surrounds all types of cells, forming a barrier between the cell's interior and the external environment. It is responsible for regulating the movement of substances in and out of the cell, thereby maintaining homeostasis.

Cytoplasm, the jelly-like substance within the cell that contains organelles and the cell's components, is present in both types of cells as well. This environment allows for cellular processes to occur, including metabolism and cell division.

In contrast, other options list structures that are not universally present in both cell types. For instance, the nucleus is a defining feature of eukaryotic cells, where it houses the cell's genetic material, while prokaryotic cells lack a nucleus, instead having their DNA located in a region called the nucleoid. Similarly, chloroplasts are specific to plant cells and some algae, used for photosynthesis and absent in prokaryotes or animal cells. Additionally, while many prokaryotic cells have cell walls, not all eukaryotic cells do, especially in animals. Thus, the plasma membrane