Question

multiple - choice question
the cell membranes job is to....
be the barrier of the cell
all of the above.
regulate the movement of molecules into and out of the cell
function as a semi - permeable \gatekeeper\ that only lets some things in and out

Explanation:

The cell membrane acts as a barrier, regulates molecular movement, and functions as a semi - permeable gatekeeper. So all the given options describe its functions.

Answer:

B. All of the above.