Both prokaryote and eukaryote cells have this structure. It helps maintain homeostasis and is a boundary between the inside of the cell and the outside environment. It is the

Respuesta :

Cell membrane would be the correct answer!

Answer:

It is the membrane.

Explanation:

The cell membrane surrounds the cytoplasm of a cell and physically separates the internal parts of the cell from the external environment. The membrane is also the gatekeeper, controlling what comes into and goes out of the cell.